1. The judgment dated 4.12.2006 in W.R No. 309 of 2005 rendered by a learned Single Judge of this court is under challenge in these four writ appeals, which we propose to dispose of by this common judgment. One of the four appellants is Shri Diptendu Bhattacharjee, the writ petitioner himself, his appeal being W.A. 80 of 2006. Other appellants were respondents in the said writ petition. 2. Challenges in the Writ Petition The selection procedure adopted by the Tripura Public Service Commission (herein after referred to as 'the Commission') as well as selection of 13 private respondents (respondent Nos. 6 to 18 in the said writ petition who are appellants in W.A.78 of 2006) for direct appointment to the posts of Assistant Professor in various disciplines of the Tripura Engineering College were assailed in the said writ petition on various grounds, the principal contention being that reservation of posts for Scheduled Tribes and Scheduled Castes done by the Commission after the selection and the oral test adopted as the only method of selection for appointment to the said posts are violative of articles 14 and 16 of the Constitution. The learned Single Judge allowed the writ petition setting aside and quashing the entire selection and appointment of 13 private respondents with direction to undertake a fresh exercise after determining and advertising which and how many of the advertised posts in different disciplines would be reserved for Scheduled Tribes and Scheduled Castes. 3. Conclusions of the Learned Single Judge The conclusions arrived at by the learned Single Judge are - (i) The selection process followed by the Commission, in pursuant to the Advertisement No. 2/2004 dated 1.3.2004, is not fair and the same is vitiated. The Government as well as the Commission ought to have notified which of the advertised posts would be considered as open category posts and which of the posts would be considered as reserved category posts and should have conducted the selection only after making known to all concerned the position as aforesaid. The Government as well as the Commission ought to have notified which of the advertised posts would be considered as open category posts and which of the posts would be considered as reserved category posts and should have conducted the selection only after making known to all concerned the position as aforesaid. The failure to notify the same and taking a decision on reservation of specific posts only after the selection was'complete have resulted in adoption of a procedure, which is not in consonance with the principle of fairness and appears to be discriminatory ; (ii) The contention that the writ petitioner having participated in the selection process cannot be permitted to challenge the selection process is not acceptable for the reason that the petitioner was not made aware at the time of advertisement or when called for participation in the selection process as well as at the time when the selection was made that the post of Assistant Professor in the discipline of Computer Science and Engineering would be reserved category post; (iii) Though normally a writ petitioner being a candidate of his chosen discipline is not entitled to challenge the selection of candidates in disciplines where the petitioner does not have the qualification to apply and is ineligible to be considered for appointment, in the instant case if the selection of private respondent Nos. 6 to 18 is allowed to go unchallenged, it would mean that the remaining four posts, which have been kept vacant would be treated as reserved for Scheduled Tribes category candidates and it would be difficult for the court to grant any relief to the petitioner ; (iv) Having permitted the petitioner to participate in the selection process where he was the only candidate in his chosen discipline (Computer Science and Engineering), the Commission would not be fair to deny appointment to the petitioner after the selection is over on the ground that the said post is a reserved category post. 4. Facts in Brief In order to understand the controversy, we may notice the factual matrix in a very short compass : The writ petitioner Shri Diptendu Bhattacharjee (appellant in W.A. No. 80 of 2006J is a Lecturer in Selection Grade in Electrical Engineering in the Tripura Engineering College. 4. Facts in Brief In order to understand the controversy, we may notice the factual matrix in a very short compass : The writ petitioner Shri Diptendu Bhattacharjee (appellant in W.A. No. 80 of 2006J is a Lecturer in Selection Grade in Electrical Engineering in the Tripura Engineering College. He obtained 70.11 per cent marks in Madhyamik Examination, 75.7 per cent marks in H.S.(+2 Stage) Examination, 69.03 per cent marks in B.E.(Electronics) Examination and 85.3 per cent marks in M.E. Tel.E. in Computer Engineering specialization with Gold Medal for securing First Class First position in the last mentioned examination. He was appointed to the post of Lecturer in 1991 in Electrical Engineering Department of the Tripura Engineering College after selection by the Commission and in due course he moved to the Selection Grade w.e.f. 9.9.2002. The Commission published an advertisement No. 2/2004, dated 1.3.2004 inviting applications for direct appointment to 17 temporary posts of Assistant Professor for Tripura Engineering College in following disciplines: - (a) Civil Engineering 4(four) (b) Mechanical Engineering 4(four) (c) Electrical Engineering 4(four) (d) Computer Science & Engineering - 1 (one) (e) Economics - l(one) CO Mathematics (g) Physics l(one) l(one) l(one) (h) Chemistry Essential qualifications for the posts have also -been indicated in the advertisement. The petitioner applied for the post of Assistant Professor in Electrical Engineering. He also filed another application for the post of Assistant Professor in Computer Science and Engineering. But, he was not found eligible for the post of Assistant Professor in Electrical Engineering. He was called for interview only for the post of Assistant Professor in Computer Science and Engineering. The other applicants for the said post were not found eligible and, therefore, her emained the sole candidate in the field for the said post. In the advertisement conspicuously there was no mention, which post and in which discipline would be for the reserved categories. As a result, the applicants had no idea whether the posts applied for in their chosen disciplines would be in general category or reserved categories. In the advertisement conspicuously there was no mention, which post and in which discipline would be for the reserved categories. As a result, the applicants had no idea whether the posts applied for in their chosen disciplines would be in general category or reserved categories. Though the petitioner felt aggrieved for refusing him to face interview for the post of Assistant Professor (Electrical Engineering), he had the impression that the post of Assistant Professor in Computer Science and Engineering being a single post would not fall in any reserved category and he being the lone candidate would be selected for and appointed to the said post in consideration of his brilliant academic record, teaching experience in the said Engineering College and his performance in the interview where he had answered correctly all the questions. But to his shock and surprise he came to know that he could not secure any position among the first nine candidates selected from UR category and the post of Assistant Professor, Computer Science and Engineering had been left vacant along with other three vacant posts which came to be automatically reserved or available only for Scheduled Tribes, 5. Grievances of the Petitioner The grievances of the petitioner as projected in the writ petition are as follows :- (i) He has been denied to be interviewed for the post of Assistant Professor (Electrical Engineering) illegally and arbitrarily; (ii) The post of Assistant Professor (Computer Science and Engineering) being a single post cannot be kept for reserved category being violative of the principles of reservation ; (iii) The oral interview only for 100 marks for selection of such important posts like Assistant Professors of the Engineering College is legally unsustainable inasmuch as the same being purely subjective test, element of arbitrariness is bound to be present; (iv) Though private respondent Nos. 13, 15 and 17 have no teaching experience in any Engineering College, they have been selected for the posts of Assistant Professor in their chosen disciplines in violation of the provisions contained in the Recruitment Rules for the said post; (v) Respondent Nos. 11, 12, 14 and 16, who have been selected for the posts of Assistant Professor are much junior to him in the grade of Lecturer in the said Engineering College. 11, 12, 14 and 16, who have been selected for the posts of Assistant Professor are much junior to him in the grade of Lecturer in the said Engineering College. His performance in the interview for the post of Assistant Professor (Computer Science and Engineering) cannot be comparable with the performance of others in other disciplines as there cannot be any uniform method or criteria for deciding the merits of the persons interviewed belonging to different disciplines. He made representations to the Secretary and Commissioner of the Higher Education of the State Government on 10.5.2005 and 6.6.2005, which, however, could evoke no favourable response. In the writ petition, he prayed for setting aside and quashing the entire selection process and directing the respondents to make discipline wise reservation. 6. Contention of the State Government The State and its other official respondents, the Commission and the private respondent Nos. 6 to 18 in the writ petition contested the claim by filing separate counter-affidavits. The contention, inter alia of the State and its other official respondents is that the Recruitment Rules for the post of Assistant Professor showing total strength to be 18 have not shown their distribution among different disciplines as that would depend on necessity of the institution from time to time. Out of 18 posts of Assistant Professors, 17 were vacant for which requisition was sent to the Commission indicating that 5 posts would be reserved for Scheduled Tribes and 3 posts for Scheduled Castes without indicating reservation against any particular discipline. It is contended that the department is not aware anything about the procedure for selection of suitable candidates adopted by the commission. As the reservation roster position was duly verified and it was found that 8 posts out of 17 would be in the reserved category, there remained only 9 posts for the general category and it was not considered necessary to earmark any particular post for the reserved category. Admitting that the representations dated 10.5.2005 and 6.6.2005 were received from the petitioner, the challenge advanced therein being confined to the selection process only adopted by the Commission, the State or other official respondents of the State have no comment to offer or decision to make. 7. Admitting that the representations dated 10.5.2005 and 6.6.2005 were received from the petitioner, the challenge advanced therein being confined to the selection process only adopted by the Commission, the State or other official respondents of the State have no comment to offer or decision to make. 7. Stand of the Commission The Commission being at the center of the challenge contended, inter alia, that there was no indication in the requisition received from the State Government, about any particular post of any particular discipline ft to be kept for the reserved category and in view of the clear provision in the Recruitment Rules and the requisition indicating requirement of different disciplines the advertisement inviting application for 17 posts was published with only indication that out of 17 posts, 5 posts would be reserved for Scheduled Tribes, 3 for Scheduled Castes. Thus only 9 posts would be available for selection from the open market. The only clarification, which was considered by Commission necessary, for the State Government to make was with regard to the candidates from Industries/Profession who may not have teaching experience or Ph.D. Degree. Thus, there was nothing wrong in the advertisement issued by the Commission, which was quite consistent with the Recruitment Rules as well as the requisition received from the State respondents and which has not been put under challenge in the writ petition. As regards the grievance of the petitioner that he was not found eligible for the post of Assistant Professor (Electrical Engineering), the contention of the Commission is that the petitioner has no basic educational qualification in Electrical Engineering. Though, he is possessing B.E. in Electronics and M.E. Ifel.E. in Computer Engineering, the requirement for the said post as per the advertisement is Ph.D. Degree with First Class at Bachelor's or Master's level in the appropriate branch of Engineering/Technology with three years experience in teaching or First Class Degree at Master's level in appropriate branch of Engineering/Technology with five years experience in teaching/Industry. He was, however, found to be the only candidate eligible for the post of Assistant Professor (Computer Science and Engineering) among four applicants, but as he Secured the marks, which placed him much below 9 UR candidates in the merit list and as there were only 9 posts out of 17 available for general category, he could not be selected for the post of Assistant Professor (Computer Science and Engineering). It is the specific contention of the Commission that the said post has never been earmarked for any reserved category before or after the selection process and that only for non-availability of any candidate within 9 successful general candidates selected on merit for the said discipline, the post had to be left vacant. As there was only one candidate belonging to Scheduled Tribes category, who was found eligible and suitable for the post of Assistant Professor in Civil Engineering, four posts out of 17 had to be left vacant due to non-availability of Scheduled Tribes candidates. Thus, there has been no discrimination in the process of selection and the Commission has riot done anything towards reservation of any particular post, much less for the post of Assistant Professors (Computer Science and Engineering). It is just happened that four posts could not be filled up the reason being non-availability of eligible persons belonging to Scheduled Tribes community. 8. Defence taken by private respondents In their joint counter-affidavit, the private respondent Nos. 6 to 18 of the writ petition/who have been selected and appointed to the 13 posts of Assistant Professors in different disciplines contended, inter alia, that purely on the basis of their merit and eligibility, they have been selected and appointed. Of them all the 9 UR candidates recommended for appointment have secured higher marks than the petitioner and for that reason alone he cannot question their selection and appointment in the disciplines for none of which the petitioner was an applicant. It is their specific contention that as their selection and appointment remained within the number of posts advertised for UR category and the posts against which they have been appointed have never been declared to be reserved their selection and appointment have nothing to be interfered with by the court. 9. Ve have heard the learned counsel for the parties Merit of the claim of eligibility for the post in electrical engineering : - Having set out the rival contentions and noticed the decisions and conclusions of the learned Single Judge above, we may now, before adverting to the principal contention, deal with the peripheral questions, the first being the grievance regarding eligibility of the petitioner for the post of Assistant Professor (Electrical Engineering) for which he was not found eligible. It is seen that the essential qualification for the said post as stated in the advertisement noticed above, is just as provided in the Recruitment Rules for the post of Assistant Professors. As he neither possessed Ph.D. Degree with 1st Class at Bachelor's or Master's level in Electrical Engineering or 1st Class Degree at Master's level in the said discipline, we are of the considered view that the Commission has rightly found the petitioner not eligible for the post of Assistant Professor (Electrical Engineering) if strictly gone by the educational qualifications and other qualifications provided in the Recruitment Rules. 10. Single Post Reservation The other contention advanced is regarding the post of Assistant-Professor (Computer Science and Engineering) for which the petitioner was found to be the only eligible candidate and according to him, the same being a single post, cannot be kept for any reserved category. On this issue, learned Single Judge held thus : 'If the said post was a reserved post, naturally the eligibility of the petitioner to participate in the selection process would have been absent. Having thus permitted the petitioner to participate in the selection process where he was the lone candidate in his chosen discipline, the Commission would not be fair to deny appointment to the petitioner after the selection is made on the ground that the said post is a reserved post by basing, their decision with reference to the common merit list prepared by the Commission'. This, in our view, has not been correctly dealt with and decided by the learned Single Judge in view of the provisions contained in the Recruitment Rules, which do not say which particular post shall be reserved for Scheduled Tribes or Scheduled Castes. It has been correctly argued by Mr. S. Deb, learned senior counsel appearing for the respondent Commission that the petitioner could not be selected for appointment to the post of Assistant Professor (Computer Science and Engineering) not because the post was reserved for Scheduled Tribes or Scheduled Castes, but because the petitioner could not come within first 9 persons in the merit list for appointment against a post available for general category. The first and foremost condition of appointment of any person to any of the 17 posts advertised is that if he is of general category, he must be one of the first 9 candidates selected on merit and only thereafter, he could be accommodated against the discipline of his choice if vacancy remains after accommodating candidates, if any, above him in the same discipline. Thus, the view that the post of Assistant Professor (Computer Science and Engineering) had been kept for reserved category illegally and arbitrarily only after the selection process and because of such reservation the petitioner could not be appointed to that post is, in our view, totally misconceived and, therefore, unsustainable in law. It is quite evident from the consistent stand of the State and the Commission that neither the post of Assistant Professor (Computer Science and Engineering) nor any other post has ever been specifically earmarked for any reserved category. Out of 17 posts advertised, 9 were available for general category, 5 for Scheduled Tribes and 3 for Scheduled Castes, as per provision in the Recruitment Rules, as correctly reflected in the advertisement published. There being no ambiguity about this position, more so neither the recruitment rules nor the advertisement having been put under challenge by the petitioner, the only acceptable view to be taken is that no post was reserved before or after the selection and it just happened that because of non-availability of four ST candidates, four posts remained vacant, one of which happened to be the post of Assistant Professor (Computer Science and Engineering). Mr. Deb has sought to emphasize that if the petitioner could secure a position among the first 9 UR candidates in the merit list, he would certainly have been appointed to the post of Assistant Professor (Computer Science and Engineering). But he secured only 16th position in the common merit list and 13th among *he UR candidates. Because of his failure to secure such a position and because of selection of more suitable candidates for 9 UR posts, all above him in the merit list, the post of his choice along with 3 others remained vacant, Mr. Deb submits. We would see later how this submission lacks merit when given closer scrutiny. 11. Because of his failure to secure such a position and because of selection of more suitable candidates for 9 UR posts, all above him in the merit list, the post of his choice along with 3 others remained vacant, Mr. Deb submits. We would see later how this submission lacks merit when given closer scrutiny. 11. Reservation after Selection It would be seen from the judgment impugned that the learned Single Judge allowed the writ petition only on the ground that the respondents did not act with fairness by not disclosing the posts which would be reserved for Scheduled Tribes and Scheduled Castes. In public employment it is of utmost-importance that the entire selection process is transparent and known to the participants well before commencement of the process and if the petitioner could know that the post for which he was found eligible was earmarked for the reserved category, he would not have participated in the selection process. Learned Single Judge has proceeded from these 'premises for taking the view that by deciding to reserve some posts including the post of Assistant Professor (Computer Science and Engineering) only after the selection process was over, the entire selection process has become vitiated. According to the learned Single Judge, it is the duty of the State respondents to declare the posts, which would be earmarked for the reserved category in order to enable the prospecting candidates belonging to the general category to decide before taking the plunge. Thus, reservation of posts after selection being the main reason for setting aside and quashing the entire selection process/which has been called into question in the present three appeals (W.A. 78/06, 79/06 and 17/07) by the State, Commission and the private respondents, it would not have been necessary for us to enter into any other controversy but for the appeal filed by the petitioner-appellant (W.A.80/06), who has impugned the same judgment on the following grounds : - (a) Viva voce cannot be the sole method of selection ; (b) Reservation should be discipline wise ; (c) The petitioner has been arbitrarily denied a call for interview for the post of Assistant Professor (Electrical Engineering). 12. 12. Method of selection and discipline wise reservation We have already dealt with and answered the third issue regarding eligibility of the petitioner for the post of Assistant Professor in Electrical Engineering and we have seen that he has indisputably no basic degree in Electrical Engineering, which is a mandatory requirement as per the Recruitment Rules and as such he has been correctly found not eligible for the same. The question whether viva voce test can be the sole method of selection or whether discipline wise reservation or earmarking of reserved post before the selection process commenced is required by law, we shall presently address them in the light of the legal position settled by the Apex Court in a line of decisions. 13. Reason for the oral test as the only method In the case on hand, the Commission has adopted viva voce test only for 100 marks to test suitability of the candidates and the reason for the same, as has been pleaded by the Commission in the counter-affidavit, is that only 19 candidates were in the field for 17 posts and, therefore, no written test was considered necessary. We are not convinced. We do not consider it correct that number of candidates only should determine the method of selection. The post of Assistant Professor in the Engineering College is not only a Gazetted Post but undoubtedly to be regarded as a high public office. In Ajay Hasia v, Khalid Mujib Sehravardi, (1981) 1 SCC 722 , the Apex Court observed as follows : - "oral interview test is undoubtedly not a very satisfactory test for assessing and evaluating the capacity and caliber of candidates, but in the absence of any better test for measuring personal characteristics and traits, the oral interview test must, at the present stage, be regarded as not irrational or irrelevant though it is subjective and based on first impression, its result is influenced by many uncertain factors and it is capable of abuse." (Emphasis ours) We pause here for a moment to remind ourselves that this observation is about measuring personal characteristics and traits only by oral interview. In our case, there is no specific contention that the test for 100 marks was only for measuring personality and character by oral test. In our case, there is no specific contention that the test for 100 marks was only for measuring personality and character by oral test. Normally, such high marks should not be only for evaluating personality and character, it ought to be for assessing depth of knowledge and command in the subjects concerned as well. Though, however, the above observation was made in the context of admission of students in Regional Engineering College, Srinagar, the Apex Court brought into its observation the matter of public employment also in the following words "We would, however, like to point out that in the matter of admission to college or even in the matter of public employment, the oral interview test as presently held should not be relied upon as an exclusive test, but may be resorted to only as an additional or supplementary test and, moreover, great care must be taken to see that persons who are appointed to conduct the oral interview test are men of high integrity, caliber and qualification." But as the marks allocated for oral interview in the said admission test was 33 V3 per cent of the total marks, it was held that such oral test was unreasonable arid arbitrary. The final view of the Apex Court in Ajay Hasia (supra) was that allocation of more than 15 per cent of the marks For the oral interview would be arbitrary and unreasonable and the same is liable to be struck down as constitutionally invalid. 14. Validity of oral test The above view has, however, been departed from in Lila Dhar v. State rf Rajasthan, (1981) 4 SCC 159 , particularly in respect of public smployment. In para 6 and 9 of the said judgment, the Apex Court held that the ratio laid down in Ajay Hasia (supra) is per incuriam and cannot be applied in cases of public employment. The relevant part of para 6 on this point reads as follows : - "On the other hand, in the case of services to which recruitment has necessarily to be made from persons of mature personality interview test may be the only way, subject to basic and essential academic and professional requirements being satisfied. The relevant part of para 6 on this point reads as follows : - "On the other hand, in the case of services to which recruitment has necessarily to be made from persons of mature personality interview test may be the only way, subject to basic and essential academic and professional requirements being satisfied. To subject such persons to a written examination may yield unfruitful and negative results, apart from its being an act of cruelty to those persons." para 9, the Apex Court further observed "The words "or even in the matter of public employment" occurring in the first extracted passage and the reference to the marks allocated for the interview test in the Indian Administrative Service examination were not intended to lay down any wide, general rule that the same principle that applied in the matter of admission to colleges also applied in the matter of recruitment to public services. The observation relating to public employment was per incuriam since the matter did not fall for . the consideration of the court in that case." 15. Necessity of common syllabus, guideline or uniform criteria Fhe Apex Court thus settled that in the matter of public employment an oral test can be the sole method for assessing the quality and suitability of the persons interviewed. But it is to be noticed that in the Dresent case not only written examination was dispensed with but the narks allocated for oral interview was as high as 100 and again, admittedly, there has been no guideline or common criteria for subjecting Jie candidates of different disciplines through same test. The petitioner-appellant has raised a very .important question regarding the method adopted for testing suitability of 19 candidates for 17 posts of different, iisciplines. As no common syllabus was formulated and made available ;o the candidates, in Ajay Hasia (supra), the Supreme Court observed ;hat 'one of the most prolific sources of error in the oral test has been the failure on the part of examiners to understand the nature of evidence and to discriminate between that which was relevant, material and reliable and that which was not. It also must be remembered that the best oral interview provides opportunity for analysis of only a very small part of a person's total behaviour. Generalisations from a single interview regarding an individual's total personality pattern have been proved repeatedly to be wrong5. It also must be remembered that the best oral interview provides opportunity for analysis of only a very small part of a person's total behaviour. Generalisations from a single interview regarding an individual's total personality pattern have been proved repeatedly to be wrong5. Though in spite of all criticism, the oral interview method is very much in vogue, but according to the Apex Court in Ajay Hasia (supra) the same should be a supplementary test only for assessing the suitability of candidates. In "Public Administration in theory and-practice", a book by M.P. Sharma, a passage relevant to the question has been quoted in Ajay Hasia (supra), the relevant part of which reads : - ''Different interviewers have their own notions of good personality. For some, it consists more in attractive physical appearance and dress rather than anything else and with them the breezy and shiny type of candidate scores highly while the rough uncut diamonds may go unappreciated. The atmosphere of the interview is artificial and prevents some candidates from appearing at their best. Its duration is short, the few questions of the hit-or-miss type, which are put, may fail to reveal the real worth of the candidate." Though oral interview method in public employment as the only test cannot per se be legally invalid in view of the decision of the Supreme Court in Lila Dhar (supra), it has to be observed in the case on hand that in the absence of any common syllabus or criteria for assessing suitability of candidates of different disciplines, the oral interview method as the only test has every possibility of suffering from uncertainty, subjectivity and other unseen vices. We are of the considered view that in such oral interview for selection of persons for different disciplines like Civil Engineering, Mechanical Engineering, Computer Science and Engineering/Mathematics, Physics, Chemistry and Economics, it is absolutely necessary to formulate a common syllabus in the event a common selection is intended without any written test. 16. Discipline-wise selection when desireable It would be seen from records that for 4 posts of Assistant Professors in Civil Engineering, there were only 5 applicants. Similarly for 4 posts in Mechanical Engineering, there were only 4 applicants and for 4 posts of Electrical Engineering, there were also 4 applicants. 16. Discipline-wise selection when desireable It would be seen from records that for 4 posts of Assistant Professors in Civil Engineering, there were only 5 applicants. Similarly for 4 posts in Mechanical Engineering, there were only 4 applicants and for 4 posts of Electrical Engineering, there were also 4 applicants. It is desirable that candidates should be selected for a particular discipline only from the applicants of that discipline if knowledge and command of the candidates in the particular subject are considered to be necessary elements in the suitability test. .If, however, personality test is intended to be the only criteria without any test in the subject concerned, then only a common selection test for candidates of different disciplines, is feasible and for that also a common syllabus or guideline is of utmost importance to prevent subjectivity oc uncertainty or personal notions of the interviewers. 17, Estoppel by conduct Mr. Deb, learned senior counsel for the respondents-appellants (Commission) has strongly argued that the petitioner-appellant cannot question the selection process after himself participating in the same, being barred by the principle of estoppel by conduct. It is true a person after participating in the selection process cannot question its validity only because he has been unsuccessful. Certainly he cannot question the composition of the Committee taking the interview or the marks allocated to him. The Supreme Court in Chandra Prakash Tiwari v. Shakuntala Shukla, (2002) 6 SCC 127 observed that estoppel by conduct can only be said to be available when there is a precise and unambiguous representation and it is on that score a further question arises as to whether there was any unequivocal assurance prompting the assured to alter his position or status. The three basic elements of the doctrine of estoppel have been referred to in Tata Iron & Steel Co. Ltd. v. Union of India (2001) 2 SCC 41 . The relevant observation appearing in para 20 is gainfully quoted below : - "20. Estoppel by conduct in modern times stands elucidated with the decisions of the English Courts in Pickard v. Sears and its gradual elaboration until placement of its true principles by the Privy Council in the case of sarat Chunder Dey v. Gopal ChunderLaha whereas earlier Lord Esher in the case of seton Laing Co. Estoppel by conduct in modern times stands elucidated with the decisions of the English Courts in Pickard v. Sears and its gradual elaboration until placement of its true principles by the Privy Council in the case of sarat Chunder Dey v. Gopal ChunderLaha whereas earlier Lord Esher in the case of seton Laing Co. v. Lafone evolved three basic elements of the doctrine of estoppel to wit: 'Firstly, where a man makes a fraudulent misrepresentation and another man acts upon it to its true detriment: Secondly, another may be where a man makes false statement negligently though without fraud and another person acts upon it: And thirdly, there may be circumstances under which, where a misrepresentation is made without fraud and without negligence, there may be an estoppel." The petitioner-appellant has not challenged composition of the interview board or h£fs not questioned the marks allotted to him. He has raised a general question regarding correctness of the selection process, i.e., oral test as the only method for selection in important public office like Assistant Professor. Such controversy is still stalking in the legal corridor. We do not think the principle of estoppel by conduct stands in the way of revisiting the issue. 18. Whether oral test vitiates the selection process It would be seen thus that the petitioner in the case on hand ha-s neither alleged anything against composition of the Selection Committee nor the marks allocated to him in the oral test which placed him much below 9 UR candidates. He has also not alleged any personal bias or mala fide in the selection process. What he has sought to question is correctness of the oral interview method as the sole test for assessing suitability of candidates of different disciplines. We have already held that if the selection is confined to personality test only, then also it is desirable that a common syllabus or guideline is formulated for uniformity in the process. If. however, suitability of :;he candidates with regard to their knowledge in respective subject or discipline is also an element of test then separate test for separate discipline is desirable. If. however, suitability of :;he candidates with regard to their knowledge in respective subject or discipline is also an element of test then separate test for separate discipline is desirable. But in view of the decision of the Supreme Court in Lila Dhar (supra) and the fact that despite of the criticism, the oral interview method continues to be very much in vogue, we are not inclined to invalidate the selection process, more so for the reason that no mala fide or personal bias has been alleged. 19. Reservation by the commission after selection The next important question, which confronts us now, relates to recommendation part of the selection process, particularly its consistency with the stand taken by the Commission. Learned Single Judge observed that the Commission itself reserved certain posts only after the selection process was over. Though we have noticed above that neither the State Government nor the Commission have declared any particular post for any reserved category either before or after the selection and it just happened that 4 posts out of 17 remained unfilled due to non-availability of Scheduled Tribes candidates and one of the 4 posts happened to be the post of Assistant Professor, Computer Science and Engineering, a closer look to the practical scenario seems to give a different picture. The principal contention of the Commission is that as only 9 posts were available for the UR category, the petitioner-appellant was required to secure a position within 9 for recommendation by the Commission for appointment to the post of his discipline. As he has got only 16th position in order of merit securing 56 marks only, he being a candidate of general category could not be recommended for appointment though the post of Assistant Professor (Computer Science and Engineering) is a single post and not earmarked for any reserved category. 20. The incongruity of the above stand would be apparent from a closer look of the merit list and the recommendations made. The overall merit list of the qualified candidates for the post of Assistant Professors, Tripura Engineering College shows the names of 19 candidates, their age. category, subjects, marks obtained and recommendation of the Commission. For better appreciation, the same is extracted below : - "Overall merit list of qualified candidates for the post of assistant professor, Tripura Engeering College SI. The overall merit list of the qualified candidates for the post of Assistant Professors, Tripura Engineering College shows the names of 19 candidates, their age. category, subjects, marks obtained and recommendation of the Commission. For better appreciation, the same is extracted below : - "Overall merit list of qualified candidates for the post of assistant professor, Tripura Engeering College SI. No. Roll No. Name Age as on 1.3.2004 Category Subject Marks Remarks obta­ined I. 12 Sri Prasun Chakraborty 41.3.26 UR Mech Engg. 69 Recom­mended 2. 21 Sri Richi Prasad Sharma 42.9.23 UR Civil Engg. 68 Recom­mended . 3. 11 Sri Arup Kr. Das Choudhuiy 41.2.03 UR Elec. Engg. 68 Recom­mended 4. 12 Sri Rup Narayan Ray 40.6.18 UR Elec. Engg. 67 Recom­mended 5. 6 Sri Sekhar Datta 40.3.28 UR Mech. Engg. 67 Recom­mended 6. 18 Sri Mariish Pal 33.2.12 UR Civil Engg. 67 Recom­mended 7. 23 Sri Sujit Kr. Pal 40.6.03 UR Civil Engg. 66 8. 11 Dr. Swapan Bhowmik 39.1.09 UR Mech. Engg. 65 9. 13 Sri Ardhendu Saha 37.9.26 UR Elec. Engg. 65 10. 9 Sri Ajoy DAs 31-09-22 SC Mech. Engg. 65 Recom­mended 11. 2 Dr. Debasish Bhattacharjee 42.7.03 UR Math 59 Recom­mended 12. 3 Sri Priya Nath Das 32.11.28 SC Elec. Engg. 59 Recom­mended 13. 2 Dr. (Smt.)Aparna Nath 40-0-22 UR Physic 58 Recom­mended 14. 7 Sri Ratal Das 33.2.0 SC Civil Engg. 58 Recom­mended 15. 1 Dr. Saroj Kr. Das 41.0.0 UR Chemistry 57 Recom­mended 16. 4 Sri Diptendu Bhattacharya 37.3.07 UR Comp. Secience & Eng.. 56 17. 3 Dr. Amitabha Saha 36.1.16 UR Chemistry 55 18. 4 Dr. Asis Mitra 40.4.27 UR Chemistry 53 19. 11 Smt. Rama Dabbarma 31.10.11 ST Civil Engg. 51 Recom­mended It would appear from the above list that only first six candidates in the merit list belonging to UR category have been recommended by the Commission, 2 for Mechanical Engineering, 2 for Civil Engineering and 2 for Electrical Engineering. It would further appear vhat Shri Sujit Kr. Pal in the 7th position secured 66 marks belonging to Civil Engineering has not been recommended as obviously there noa vacancy after recommending 2 from UR in second and sixth positicns, one from Scheduled Tribes in 19th position and one from Scheduled Castes in 14th position. Thus, though he has scored 7th position in the merit list, he could not be recommended for want of vacancy. Thus, though he has scored 7th position in the merit list, he could not be recommended for want of vacancy. But sa;ne is not the case with Dr. Swapan Bhowmik and. Shri Ardhendu Saha, who are in 8th and 9th position in the merit list belonging to Mechanical Engineering and Electrical Engineering respectively. Dr. Swapan Bhowmik secured 65 marks with 8th position, but has not been recommended though there exists one vacancy in the said discipline after recommending two candidates from UR (serial No. 1 and 6) and one from Scheduled Castes (serial No. 10). Similarly, Shri Ardhendu Saha in 9th position securing 65 marks has not been recommended for Electrical Engineering though there remains one vacancy after recommending two from UR (serial Nos. 3 and 4) and one from SC (serial No. 12). The reason is obviously to keep two vacancies reserved for Scheduled Tribes in the said two disciplines. Again, Dr. Debashis Bhattacharjee (UR) at serial No. 11 of the merit list has been recommended for appointment to the post of Assistant Professor, Mathematics. As one Scheduled Castes candidate (Shri Ajoy Das) has scored 10th position in the common merit list. Dr. Bhattacharjee would move up from llth to 10th position of UR candidates. Again, as 7th position holder (UR) could not be recommended for want of vacancy, Dr. Bhattacharjee moves up further and conies for one of the nine vacancies for general category. Therefore, there is nothing wrong in his selection. Curiously enough, the Commission has recommended Dr. (Smt.) Aparna Nath (UR) at serial No. 13 and Dr. Saroj Kr. Das at serial No. 15 of the merit list for the posts of Physics and Chemistry. As there is no reservation against any particular post, the question that would spring up and loom large why the Commission refused to recommend Dr. Swapan Bhowmik and Shri Ardhendu Saha, who secured 8th and 9th position and though there exists vacancy in their respective discipline? Why, instead, the Commission has recommended two others of general category whose position are much below, at 13th and 15th of the merit list? Thus the argument of the Commission that the petitioner-appellant could not be recommended only because he could not secure a position in the merit list of first 9 UR candidates is totally wrong and baseless and misplaced. 21. Thus the argument of the Commission that the petitioner-appellant could not be recommended only because he could not secure a position in the merit list of first 9 UR candidates is totally wrong and baseless and misplaced. 21. Wednesbury test It is, thus, evident that though the Recruitment Rules for the posts have not earmarked any particular post in any discipline for any reserved category, which is the consistent stand of the State and the Commission and proceeding therefrom it can be said that the first 9 UR candidates in the merit list are entitled to be recommended for a appointment against the posts of their respective disciplines, subject, however, to availability of vacancies. Dr. Swapan Bhowmik and Shri Ardhendu Saha have not been recommended by the Commission for undisclosed reason inspite of availability of vacancies. The undisclosed but obvious reason must be that the Commission arbitrarily . and uncalled for decided to earmark and keep aside one post in Mechanical Engineering and another in Electrical Engineering as reserved for Scheduled Tribes only. This, in our considered view, cannot be the business of the Commission. It has gone beyond its bounds. The question is whether such discretion exercised by the Commission is at all conferred by or consistent with the law and whether the same can stand Wednesbury test particularly when neither the Recruitment Rules contemplate nor the State Government required the Commission to do the same. For applying the Wednesbury principle, it can be said that interference by the court is not permissible unless one or more of the following conditions are satisfied, viz., the order is contrary to law, or ° irrelevant factors have been considered, or relevant factors have not been considered, or the decision is one that no reasonable person would have taken. In G. B, Mahajan v. Jalgaon Municipal Council, (1991)3 SCC 91 , the pertaining question was who is a 'reasonable man'. It has been pointed out in the said judgment that the test of a 'reasonable man or the "man on the Clapham omnibus" as known in the law of torts is not applicable in case of Wednesbury unreasonableness. Hence, in condemning unreasonable administrative action, the court enquires whether the decision is one which a reasonable body could have reached. In other words, the court allows some latitude for the range of differing opinions which may fall within the bounds of reasonableness. Hence, in condemning unreasonable administrative action, the court enquires whether the decision is one which a reasonable body could have reached. In other words, the court allows some latitude for the range of differing opinions which may fall within the bounds of reasonableness. Thus where no reasonable person can find the decision reasonable, Wednesbury permits the court to interfere with the decision. 22. Recommendation of the commission fails Wednesbury tes It is well-settled and needs no dilation that the duty of the Commission is only to recommend names after selection for the advertised posts. It can never be the duty of the Commission to decide even by implication which post should be earmarked for any reserved category, a function exclusively within the domain of the State Government, more, particularly the Education Department and the institution concerned, to be performed in accordance with the recruitment rules and other relevant laws. As the Recruitment Rules do not provide that any particular post shall be earmarked for any reserved category, the concerned respondent or the authority of the institution could decide the question after receiving the merit list from the Commission on the basis of the requirement, necessity and priority with due regard to the merit position of the candidates. The decision as to which four posts should remain vacant for non-availability of four Scheduled Tribes candidates should not have been taken by the Commission. It acted unreasonably and arbitrarily by not recommending 8th and 9th position holders and instead recommending persons at 13th and 15th of the merit list. The decision of the Commission thus fails Wednesbury test leaving the court to interfere with the same, which we are inclined to do. 23. Submission on fate of the private appellants At this juncture, Mr. S. Talapatra, learned senior counsel appearing for the private respondents has placed a submission that in the event of setting aside and quashing of the selection and appointment of the private appellants, they would be simply thrown out of employment for the reason that the lower posts earlier held by them, which had fallen vacant following their appointment to the posts of Assistant Professor, have already been filled up. That apart, the interest of the institution would also greatly suffer as there would be almost no teacher in the grade of Assistant Professor in such an eventuality. That apart, the interest of the institution would also greatly suffer as there would be almost no teacher in the grade of Assistant Professor in such an eventuality. These extraneous circumstances or resultant consequences cannot have any relevance to the issues which precisely are correctness and legality of the selection process and the recommendations made by the Commission we are called upon to decide. Our inquiry thus stands restricted to the correctness of the findings of the learned Single Judge with regard to the aforesaid issues in the facts situation of the case and the legal positions noticed above. 24. Submission on roster mechanism Mr. Talapatra advanced another submission that if the hundred point roster, which starts from roster point 3 in the present case, is pressed into service in a different way by first accommodating all selected candidates of a particular stream against the allotted slots for UR category in the roster, then irrespective of the merit position. Dr. (Smt.) Aparna Nath and Dr. Saroj Kr. Das can be accommodated leaving two vacancies in the stream of Electrical and Mechanical Engineering as those vacancies would fall in the slots of the roster reserved for Scheduled Tribes. We are unable to understand and appreciate this submission at all. What we understand is that the roster mechanism is not a law by itself, but is only a means to achieve the reservation target. By no ingenious application of the roster the claim of the persons who have secured positions in the merit fist within the range of vacancies available for general category can be defeated. There is absolutely no problem about a the reservation of posts in the present imbroglio. Out of 3 posts for Scheduled Castes 3 candidates have been recommended and out of 5 posts for Scheduled Tribes, one has been recommended. In such a situation, what the law of reservation requires is that 4 posts out of-17 are to be left vacant for that category, no matter in whatever discipline, such vacancies may fall. Thus, application of the roster mechanism in whatever way, the State and Commission may intend to do, there is no escape from recommending and appointing 9 candidates of UR category as per the merit list. For the reasons aforementioned, the submissions of Mr. Talapatra merit no consideration, 25. Thus, application of the roster mechanism in whatever way, the State and Commission may intend to do, there is no escape from recommending and appointing 9 candidates of UR category as per the merit list. For the reasons aforementioned, the submissions of Mr. Talapatra merit no consideration, 25. The upshot of the above discussion may now be summed up, thus : (i) The selection process of oral test for 100 marks though not a satisfactory method, the same need not be interfered with in view of the decision of the Supreme Court in Lila Dhar (supra) and there being no allegation of bias by the petitioner with regard to the selection and the marks allocated to him. We, however, hasten to add that if personality traits as well as depth of knowledge of the candidates in the subject concerned are to be assessed, it is desirable that selection should be separately done for every discipline in accordance with a syllabus to be formulated. If personality traits only are to be assessed by an oral test for the candidates of all disciplines, then also a common syllabus, without any reference to any particular subject, is required to be formulated for the purpose of such test. The reason is that, as pointed out by the Apex Court in Ajay Hasia (supra), oral test is undoubtedly not a very satisfactory test, as there remains every possibility of subjectivity and personal notions of the interviewers about personality tainting the selection. Though there is no such allegation of personal bias from the petitioner, we have made the above observation as a note of caution; (ii) As the selection process and the merit list (other than the recommendation part) on the basis of the marks assigned stand the scrutiny of rule of subjectivity and personal bias, the next question confronting the same is whether by not declaring or indicating the posts to be reserved for Scheduled Castes and Scheduled Tribes before ft the oral test, the entire selection process stood vitiated for the reasons explained by the learned Single Judge? As we have noticed above, the Recruitment Rules for the said posts have no provision to reserve any particular post of any particular discipline for the Scheduled Tribes or Scheduled Castes. Consistent with the said Rules, the advertisement in question also has not indicated reservation against any particular post. As we have noticed above, the Recruitment Rules for the said posts have no provision to reserve any particular post of any particular discipline for the Scheduled Tribes or Scheduled Castes. Consistent with the said Rules, the advertisement in question also has not indicated reservation against any particular post. Instead, the only indication given in the advertisement is that out of 17 posts advertised, 5 shall be reserved for Scheduled Tribes and 3 for Scheduled Castes. The intention is obvious. In view of non-availability of sufficient number of suitable candidates from the reserved categories, it is always difficult to say if any post in a particular discipline is reserved for a particular reserved category, whether suitable candidate from that category would at all be available. In the event of non-availability of such candidate, the said particular discipline may suffer indefinitely. The percentage of reservation fixed by the relevant Act being the target to achieve in the public employment, it was perhaps considered necessary to provide some flexibility in the Recruitment Rules to enable the Commission to select suitable candidates from the reserved category for the post of any discipline advertised. Be that as it may, as the Recruitment Rules and the advertisement in question have not been assailed in the present proceeding, we are unable to subscribe to the view of the learned Single Judge that only for failure to earmark particular post for a reserved category before the test, the entire selection process stood vitiated. We are, therefore, of the view that on this ground also the selection process and the merit list call for no interference. Here also we intend to add that it is always desirable to indicate in the advertisement, whenever issued, the posts and the number of posts in the disciplines which are to be reserved depending on necessity, priority and interest of the institution which may vary from year to year. Here also we intend to add that it is always desirable to indicate in the advertisement, whenever issued, the posts and the number of posts in the disciplines which are to be reserved depending on necessity, priority and interest of the institution which may vary from year to year. (iii) As regards the consistent stand of the State Government as well as the Commission that there being no reservation against any particular post and only 9 posts out of 17 being available for the general category candidates, the petitioner could not be appointed as he stood at 16th position in the merit list, we quite understand and appreciate this stand only when it comes to the claim of the petitioner to be recommended against the single post of Assistant Professor in Computer Science and Engineering. Accepting this stand, we reject the contention of the petitioner that the said post being, a single post cannot come within the reservation net. But we fail to understand why the Commission did not recommend the candidates (UR) at 8th and 9th position of the merit list though vacancy exists in their respective disciplines. In its pleading the Commission could not satisfactorily show any justifiable reason for the same. This leaves no doubt in our mind that the Commission has by implication, reserved two vacancies in the Electrical and Mechanical Engineering for the Scheduled Tribes community, which the commission has no legal sanction to do. Thus, the decision of the Commission not to recommend the selected candidates of general category at 8th and 9th position of the merit list is wrong, arbitrary, illegal, capricious and unsustainable in law. If the selection process and the merit list are to survive, both the selected candidates aforementioned, have to be recommended as otherwise the consistent plea of the State and the Commission that the petitioner-appellant could not be recommended for appointment because of his poor performance in the interview and failure to come within the first 9 UR candidates would turn to be a use only. (iv) There would thus be 9 candidates of general category (1 to 6, 8, 9 and 11) entitled for appointment to the posts of Assistant Professor in their respective discipline and, therefore, no more candidate of general category can be appointed, there remaining no vacancy. The Commission has recommended 3 candidates from Scheduled Castes category and only 1 candidate from Scheduled Tribes. The Commission has recommended 3 candidates from Scheduled Castes category and only 1 candidate from Scheduled Tribes. Thus there must remain four vacant posts for Scheduled Tribes, which would inevitably fall in the disciplines of Economics, Chemistry, Physics and Computer Science and Engineering, It would be seen that the single post each in Economics, Computer Science and Engineering have been left vacant, but the single post of Assistant Professor each in Physics and Chemistry have been recommended for appointment by Dr. (Smt.) Aparna Nath and Dr. Saroj Kr. Das at serial Nos. 13 and 15 of the merit list. Obviously, if the two more reserved posts for Scheduled Tribes are to be left vacant, the aforesaid two posts in Physics and Chemistry cannot be filled up. Thus, Dr. (Smt.) Nath and Dr. Das having been already appointed against those posts in violation of the rules, the question about their fate in the event of treating those post vacant has to be decided by the State Government only. It may, however, be observed that if their appointments are intended to be protected in the interest of the institution, the State Government may either dereserve the said posts for the time being or create ex-cadre posts in the respective subjects leaving unfilled the said two cadre posts in the respective discipline, which may be carried forward for the Scheduled Tribes Community. Thus, there would remain 4 vacancies for the said community in the cadre service if the above two candidates are accommodated against ex-cadre posts ; (v) The petitioner appellant being placed at 16th position of the merit list, cannot claim recommendation for appointment to the discipline of his choice and, therefore, his challenge to the selection process on the ground that the post being a single post cannot be treated as reserved, is not tenable in law. The post is not reserved and has never been declared reserved. It being vacant has just fallen in the share of Scheduled Tribes. 26. For the reasons and discussions aforementioned, the three appeals (W.A.78/06, 79/06 and 17/07), subject to what we have observed above, are found to have merit and the same are accordingly allowed. The appeal by the petitioner-appellant (W.A.80/06) as well as his writ petition (W.P.(C) 309 of 2005] having no merit stand dismissed. For the same reason, the judgment of the learned Single Judge, impugned herein, is set aside and quashed. The appeal by the petitioner-appellant (W.A.80/06) as well as his writ petition (W.P.(C) 309 of 2005] having no merit stand dismissed. For the same reason, the judgment of the learned Single Judge, impugned herein, is set aside and quashed. It is provided that the selection process and the merit list (excluding the recommendation part) are valid, The Commission shall recommend Dr. Swapan Bhowmik and Shri Ardhendu Saha for appointment to the posts of Assistant Professor in Mechanical Engineering and Electrical Engineering respectively. The State respondents shall decide about the fate of Dr. (Smt.) Aparna Nath and Dr. Saroj Kr. Das either by derserving the posts or by creating ex-cadre posts to accommodate them in the light of our observation made above. The State Government shall also be at liberty to decide about the petitioner-appellant, Diptendu Bhattacharjee, on the basis of the merit list, if interest of the institution so demands for filling up of the post of Assistant Professor in Computer Science and Engineering, which can also be done in the same way, either by dereservation or by creation of ex-cadre post. 27. Having regard to the facts and circumstances of the case, there shall be no order as to cost.