Judgment :- 1. This appeal is filed by the petitioners against the judgment of the learned single judge dismissing their Original Petition No. 3824 of 1979. The relevant facts necessary for the disposal of this appeal may be stated briefly as follows: The two appellants and respondents 3 to S joined the Ground Water Wing of the Agricultural Department as senior Drillers. It is not disputed that the appellants entered that cadre earlier than respondents 3 to 5 and were therefore seniors in the cadre of senior Drillers. Whereas the appellants hold the qualification of Diploma in Mechanical Engineering, respondents 3 to 5 hold regular Degree of Bachelors in Mechanical Engineering. The qualifications and method of appointment to the several posts in the Ground Water Wing Department are governed by Ext. P-4 dated 7th May, 1976. The post of senior Drillers could be filled up by direct recruitment, the essential educational qualification being a Degree or Diploma in Mechanical Engineering or in Mining and experience of three years in a Governmental organisation to have familiarity with water well drilling and construction. The next promotional post under Ext.P4 is that of Junior Drilling Engineer now re-designated as Assistant Engineer (Drilling). This post could be filled up by promotion from the category of senior Drillers and in the absence of appropriate candidates being available, by direct recruitment. For promotion to the post of Junior Drilling Engineer, the educational qualifications prescribed are: a Degree in Mechanical or Agricultural Engineering and experience in water well drilling rigs of net less than one year in a Governmental organisation or Diploma in Mechanical Engineering or Agricultural Engineering with water well drilling rigs experience of not less than three years. The appellants and respondents 3 to 5 were promoted on different dates to the cadre of Junior Drilling Engineers. All the counsel are agreed that the following could be taken as their respective dates of promotion to the cadre of Junior Drilling Engineers: The appellants and respondents 3 and 5 were further promoted on a provisional basis to the next higher cadre of Drilling Engineers, now redesignated as Assistant Executive Engineer (Drilling). Whereas appellant No.1 came to be provisionally promoted on 2-5-1981, respondent No.3 came to be provisionally promoted on 4-10-1979 and the 5th respondent came to be provisionally promoted on 29-5-1980. Whereas appellant No.1 came to be provisionally promoted on 2-5-1981, respondent No.3 came to be provisionally promoted on 4-10-1979 and the 5th respondent came to be provisionally promoted on 29-5-1980. So far as respondent No. 4 is concerned, it was stated at the Bar that he was provisionally promoted with effect from 24-10-79 which order has been subsequently cancelled. 2. The qualifications for earning eligibility for promotion on regular basis (described as transfer) to the cadre of Drilling Engineers are as follows: (i) A degree in Mechanical or Agricultural Engineering (ii) Five years' experience as Junior Drilling Engineer or Agricultural Engineer; or (i) A Three year Diploma in Mechanical Engineering (ii) Ten years' experience as Junior Drilling Engineer or Agricultural Engineer; or (i) A Three year Diploma in Mechanical Engineering. (ii) Ten years' experience as Junior Drilling Engineer or Agricultural Engineering Supervisor. The appellants have challenged the orders of provisional promotion of respondents 3 to 5, Exts. P9, P10 and P12. Ext.P10 having subsequently been cancelled, it is unnecessary to examine the case of the appellants in that behalf. The other prayer of the appellants is for declaring as void the qualification regarding the period of experience prescribed by Ext. P.4 differently for the Graduates and the Diploma-holders, on the ground that it is violative of Art.14 of the Constitution. 3. We shall first take up for consideration the appellants' contention that the prescription by Ext. P-4 different periods of experience for the Degree-holders and Diploma-holders is violative of Art.14 of the Constitution. The contention of Shri Sugathan, the learned counsel for the appellants, is that the Diploma-holders and Graduates both haying come by the process of promotion to the cadre of Junior Drilling Engineers, it was not permissible for the State to prescribe different qualifications regarding experience to the Degree-holders and Diploma-holders for the purpose of promotion to the next higher cadre of Drilling Engineers. He submitted that both the Diploma-holders and the Graduates are treated eligible and suitable for the post of Junior Drilling Engineers. A further differentiation could not be made between them on the basis of their educational qualifications. It was submitted that there was no justification to prescribe a lower period of five years' experience for Graduates and a higher period of 10 years' experience for Diploma-holders. It was contended that this was clearly violative of Art.14 of the Constitution. A further differentiation could not be made between them on the basis of their educational qualifications. It was submitted that there was no justification to prescribe a lower period of five years' experience for Graduates and a higher period of 10 years' experience for Diploma-holders. It was contended that this was clearly violative of Art.14 of the Constitution. In support of this contention, reliance was placed on the judgment of a learned single judge of this Court reported in 1983 KLT 987 between Pushpadharan v. Food Corporation of India, The appellants' counsel cannot however place reliance on the said decision of the learned single judge as it is subject-matter of Writ Appeals No. 430 and 433 of 1983. 4. What has been done in this case by Ext. P-4 is to prescribe qualifications for promotion to the cadre of Drilling Engineers from the cadre of Junior Drilling Engineers. Certain educational qualification and experience have been prescribed. So far as Graduates are concerned, experience prescribed is five years as Junior Drilling Engineer or Agricultural Engineer and so far as Three year Diploma-holders in Mechanical Engineering are concerned, the experience required is 10 years as Junior Drilling Engineer or Agricultural Engineer or Agricultural Engineering Supervisor. It appears to us well settled that the rule making authority is entitled to prescribe higher educational qualifications or experience for the next higher promotional post provided the qualifications prescribed are relevant and have a nexus with the duties and responsibilities required to be discharged and attached to the promotional post. That is what stands settled by the Supreme Court in its decision reported in AIR 1974 SC 1 (State of Jammu and Kashmir v. T. N. Khoss). That is what stands settled by the Supreme Court in its decision reported in AIR 1974 SC 1 (State of Jammu and Kashmir v. T. N. Khoss). The Supreme Court has observed in Para.40 of the judgment as follows: "On the facts of the case, classification on the basis of educational qualifications made with a view to achieving administrative efficiency cannot be said to rest on any fortuitous circumstances and one has always 10 bear in mind the facts and circumstances of the case in order to judge the validily of a classification " In Para.40A, the Supreme Court further stated: "Educational qualifications have been recognized by this Court as a safe criterion for determining the validity of classification " In Para.52 of the judgment, the Supreme Court further observes: "Logically, if persons recruited to a common cadre can be classified for purposes of pay on the basis of their educational qualifications, there could be no impediment in classifying them on the same basis for purpose of promotion. The ratio of Roshan Lal's case can at best be an impediment in favouring persons drawn from one source as against those drawn from another for the reason merely that they are drawn from different sources." In Para.55 it is further observed by the Supreme Court as follows: "We are therefore of the opinion that though persons appointed directly and by promotion were integrated into a common class of Assistant Engineers, they could for purposes of promotion to the cadre of Executive Engineers, be classified on the basis of educational qualifications. The rule providing that graduates shall be eligible for such promotion to the exclusion of diploma-holders does not violate Art.14 and 16 of the Constitution and must be upheld." It is therefore clear that mere prescription of higher qualifications for the promotional post is not perse violative of Art.14 of the Constitution. It was therefore open to the rule making authority to prescribe qualifications which are higher than the one which the persons concerned were required to possess for holding the post of Junior Drilling Engineer when prescribing qualification for the post of Drilling Engineer. It is obvious that the qualifications prescribed for the post of Drilling Engineer are higher qualifications. It was therefore open to the rule making authority to prescribe qualifications which are higher than the one which the persons concerned were required to possess for holding the post of Junior Drilling Engineer when prescribing qualification for the post of Drilling Engineer. It is obvious that the qualifications prescribed for the post of Drilling Engineer are higher qualifications. The qualifications for the post of Junior Drilling Engineer are a Degree in Mechanical or Agricultural Engineering with one year's experience in water well drilling in Government organisations or Diploma in Mechanical or Agricultural Engineering with three years' experience in water well drilling rigs. Though the Graduates as well as Diploma holders are made eligible for promotion to the post of Drilling Engineers, a higher experience has been prescribed, namely, five years in respect of Graduates as Junior Drilling Engineer or Agricultural Engineer or 10 years' experience as Junior Drilling Engineer or Agricultural Engineer for Diploma Holders. It is therefore obvious that it is in the matter of experience that a higher qualification has been prescribed for the promotional post of Drilling Engineer. The principle laid down by the Supreme Court to the effect that higher educational qualifications can be prescribed for the next higher promotional post applies with equal force in regard to prescription of higher experience as one of the qualifications for me promotional post. Hence it is obvious that mere prescription of higher qualification by way of higher period of experience for the promotional post of Drilling Engineer is not per se violative of Art.14 of the Constitution. 5. The contention of the appellants however is that whereas five years' experience has been prescribed for Graduates and 10 years' experience has been prescribed for Diploma-holders and this is violative of Art.14 of the Constitution. We have already observed that what has been done by the rule-making authority in prescribing different period of experience is to prescribe a higher period of experience for the promotional post of Drilling Engineer and the rule-making authority has the necessary competence to prescribe higher qualifications. The appellants cannot contend that mere prescription of higher qualifications is per se violative of Art.14 of the Constitution. They can challenge the prescription of higher qualification only by pleading and proving that such prescription is not relevant and has no nexus with the duties and responsibilities of the Drilling Engineer. The appellants cannot contend that mere prescription of higher qualifications is per se violative of Art.14 of the Constitution. They can challenge the prescription of higher qualification only by pleading and proving that such prescription is not relevant and has no nexus with the duties and responsibilities of the Drilling Engineer. The only pleadings of the appellants in this behalf are those contained in Grounds 5, 6 and 7 of the Original Petition. For the sake of convenience, the same are extracted below: "5. The method of appointment to the post of Senior Driller is by way of direct recruitment by the Public Service Commission. To this post the qualification prescribed is only a Degree or Diploma in Mechanical Engineering or in mining and familiarity with water well drilling and construction for three years in a Government organisation. So, both the Degree-holders as well as the Diploma-holders are eligible to apply for the post of Senior Driller by direct recruitment. But in the matter of promotion to the post of Junior Drilling Engineer (redesignated as Assistant Engineer) the qualification relating to experience differs. In the case of Degree-holders the experience to be acquired is limited to that of one year only whereas in the case of Diploma holders it is three years. This is highly discriminatory. It Is with the intention of willfully delaying promotions legitimately due to the Diploma-holders. By virtue of this provision In Ext. P4 a Degree-holder gels promotion earlier than a Diploma-holder in violation of R.27 (c) of the Kerala State and Subordinate Services Rules. (6) Prescription of different periods of experience as qualification to be acquired for promotion to the posts of Junior Drilling Engineer and Drilling Engineer in the case of Degree-holders is violative of Art.14 and 16 of the Constitution and hence liable to be struck down. (7) It is to be noted that in Ext. P.5 no distinction is drawn between a Degree-holder and a Diploma-holder in the matter of acquisition of the qualification of experience to be promoted as Master Driller. (7) It is to be noted that in Ext. P.5 no distinction is drawn between a Degree-holder and a Diploma-holder in the matter of acquisition of the qualification of experience to be promoted as Master Driller. The same principle ought to have been applied in the mailer of promotion to the posts of Junior Drilling Engineer and Drilling Engineer." It is clear from the pleadings that the appellants have nowhere pleaded that the requirements of higher experience so far as Diploma holders are concerned is irrelevant and has no nexus with the duties and responsibilities attached to the post of Drilling Engineer. The appellants would succeed only by establishing that the requirement of 10 years' experience is irrelevant or has no nexus with the duties and responsibilities attached to the post of Drilling Engineer. But we find total absence of pleadings in this behalf. The Supreme Court has pointed out in Para.26 and 27 of the judgment in AIR 1974 SC 1, as follows: "Respondents have assailed the classification in the clearest terms but their challenge is purely doctrinaire. "Academic or technical qualification can be germane only at the time of initial recruitment; for purposes of promotion efficiency and experience alone must count" this is the content of their challenge. The challenge, at best, reflects the respondents' opinion on promotional opportunities in public service and one may assume that if the roles were reversed, respondents would be interested in implementing their point of view. But we cannot sit in appeal over the legislative judgment with a view to finding out whether on a comparative evaluation of rival theories touching the question of promotion, the theory advocated by the respondents is not to be preferred. Classification is primarily for the legislature or for the statutory authority charged with the duty of framing the terms and conditions of service; and if, looked at from the standpoint of the authority making it, the classification is found to rest on a reasonable basis, it has to be upheld." Our reason for saying this is to emphasize that the respondents ought to have furnished particulars as to why, according to them, the classification between diploma-holders and degree-holders is not based on a rational consideration having nexus with the object sought to be achieved. In order to establish that the protection of the equal opportunity clause has been dented to them, it is not enough for the respondents to say that they have been treated differently from others, not even enough that a differential treatment has been accorded to them in comparison with others similarly circumstanced. Discrimination is the essence of classification and does violence to the constitutional guarantee of equality only if it rests on an unreasonable basis. It was therefore incumbent on the respondents to plead and show that the classification of Assistant Engineers into those who hold diplomas and those who hold degrees is unreasonable and bears no rational nexus with its purported object Rather than do this, the respondents contended themselves by propounding an abstract theory that educational qualifications are germane at the stage of initial recruitment only. Omission to furnish the necessary particulars was construed by this Court in two cases as indicating that the plea of unlawful discrimination had no basis " The position in this case is identical in that the appellants have not made any averments in support of their case that the prescription of higher experience for Diploma-holders has no nexus with the object sought to be achieved. In the absence of clear averments in this behalf the appellants' challenge based on Art.14 must fail. 6. Hence we bold that the appellants have failed to establish that the prescription of higher experience for Diploma Holders by Ext.P.4 for Drilling Engineers is violative of Art.14 of the Constitution. 7. The only other contention that survives for examination is in the matter of according provisional promotion that the appellants have been discriminated against. It is not disputed that the appellants as well as respondents 3 to 5 did not possess the prescribed qualifications for the post of Drilling Engineer when they came to be promoted to that cadre on a provisional basis. It is clear from R.31 of the Kerala State and Subordinate Services Rules that when provisional promotions are required to be made, otherwise than in accordance with the Rules, promotions have to be made on the basis of relative seniority. Hence provisional promotions to the cadre of Drilling Engineers were required to be made taking into consideration the relative seniority of the parties in the cadre of Junior Drilling Engineers. Hence provisional promotions to the cadre of Drilling Engineers were required to be made taking into consideration the relative seniority of the parties in the cadre of Junior Drilling Engineers. Whereas the first appellant was promoted to the post of Junior Drilling Engineer on 26-3-80, the 5th respondent was promoted to that cadre on 24-6-80. Therefore in the cadre of Junior Drilling Engineers the first appellant was senior to the 5th respondent. It is therefore obvious that according of earlier promotion to respondent No.5 even though on a provisional basis was in contravention of R.31 of KS & SSR. The first appellant should have been promoted to the cadre of Drilling Engineer on a provisional basis as on the date on which respondent No 5 was promoted, namely, 29th May, 1980. The only direction that we need issue in these circumstances is to direct the 1st respondent to pay the difference in salary to the appellant No.1 on the basis that he must be regarded as deemed to have been promoted to the cadre of Drilling Engineer (redesignated now as Assistant Executive Engineer (Drilling)) on a provisional basis from 29-5-1980. Therefore, we direct that the difference in salary for the period from 29-5-1980 to 2-5-1981 shall be calculated and paid to the first appellant, as expeditiously as possible. 8. So far as respondent No. 3 is concerned, he is admittedly senior to the 1st appellant in the cadre of Junior Drilling Engineers and therefore the appellants cannot make any grievance about his earlier promotion to the cadre of Drilling Engineers. So far as 4th respondent is concerned, his promotion having since been cancelled, no claim has been made by the appellants against him. For the reasons stated above, the appeal is partly allowed. The judgment of the learned single judge is modified and respondent No.1 is directed to treat the first appellant as deemed to have been promoted on a provisional basis to the cadre of Drilling Engineer with effect from 29-5-1980. The 1st respondent is also directed to accord him the difference in salary on that basis as expeditiously as possible. The appeal in other respects stands dismissed. No costs. Partly Allowed.