JUDGMENT P.D. Desai, C.J.—The constitutional validity of Col. No. 11, clause No, 1 of the Recruitment and Promotion Rules for the post of Superintending Engineer (Civil), Class-I (Gazetted), in the Public Works Department of the Himachal Pradesh (8th Amendment) Rules, 1983 (hereinafter referred to as the Amendment Rules) is mainly under challenge herein. 2. The impugned amendment, (Annexure P-6), confines the promotional avenue to the post of Superintending Engineer (Civil), Class-1, to Executive Engineer (Civil) holding recognised degree in Civil Engineering or equivalent with at least seven years regular or regular combined with ad-hoc service as Executive Engineer (Civil). Prior to the enactment of the Amendment Rules, the promotional Superintending Engineers, Diploma Holders could not be made eligible. 3. In the State of Jammu and Kashmir v. Triloki Nath Khosa and others, [AIR 1974 SC 1], it has been ruled in no uncertain terms that formal education may not always produce excellence but a classification founded on variant educational qualification is, for the purposes of promotion to a higher post, not unjust on the face of it The onus, therefore, lies on a person challenging rules which make classification based on educational qualifications to prove the plea of discrimination and to adduce cogent and convincing evidence in support thereof. It has been further ruled in the said decision that the State is entitled to take into account the factor of achieving administrative efficiency and that if the classification is clearly co-related to such object, it cannot be said to be invalid, for, higher educational qualifications are at least a presumptive evidence of a higher mental equipment. Even where the employees are integrated into a common class, they could, for the purposes of promotion to a higher cadre, be classified on the basis of educational qualifications, 4. In the instant case, as the affidavit-in-reply points out, the classification between the Degree Holders and Diploma Holders for the purposes of promotion to the higher post has been made bearing in mind the nature and responsibilities of duties of the higher post and with a View to recruiting for the higher post persons who possess better qualifications so as to be able to render best services. Besides, it has also been pointed out that for the post of Superintending Engineer in the neighbouring States as well as in the Central Public Works Department, similar eligibility qualification is prescribed. Besides, it has also been pointed out that for the post of Superintending Engineer in the neighbouring States as well as in the Central Public Works Department, similar eligibility qualification is prescribed. Having regard to the facts and circumstances of the case, as avenue was open to Executive Engineers (Civil) holding recognised degree in Civil Engineering or equivalent with at least 7 years regular service or ad-hoc or both services as Executive Engineer (Civil) and Diploma Holder Executive Engineers who had completed 10 years service as such and were 45 years of age on September 10, I 1973. 5. The precise submission on behalf of the petitioner is that the cadre of Executive Engineers consisting of Degree Holders and Diploma Holders was an integrated cadre and that the promotional avenue from that integrated cadre could not have been validly restricted only to the Degree Holders and that any rule restricting promotional avenue only to Degree Holders is discriminatory since there is no valid basis for classification. The submission, in other words, is that since the Degree Holders and Diploma Holders have been equated for all purposes and are governed by the same conditions of service in the cadre of Executive Engineer, any discrimination against Diploma Holders on the basis of educational qualifications for the purpose of promotion to the post of Superintending Engineer is wholly arbitrary. 6. In the affidavit-in-reply filed on behalf of the respondents, three factors have been relied upon to sustain the validity of the impugned rules; first, in the neighbouring States of Punjab and Haryana and in the Central Public Works Department, there is no provision for promotion of Diploma Holders to the post of Superintending Engineer, secondly, the rule was amended bearing in mind the conditions of efficiency and for securing the best talent or services in the higher post and, thirdly, having regard to the nature and responsibility of the job, qualifications required therefor and efficiency and other conditions germane to the discharge of duties at the level of indicated above, it is not possible to hold that the impugned rules are arbitrary or discriminatory in nature and that, therefore, they are violative of the quarantee of equality enshrined in Articles 14 and 15 of the Constitution. 7. 7. The alternative submission was that even assuming that the rules are constitutionally valid, they should not be allowed to operate retrospectively so as to result in the reversion of Diploma Holders who are already promoted on ad-hoc basis prior to the enactment of the Amendment Rules. The submission cannot be entertained for obvious reasons. In the first place, promotions of Diploma Holders to the pests of Superintending Engineers made prior to the enactment of the Amendment Rules are admittedly on ad-hoc basis. An ad-hoc promottee has no vested right to hold the post. He cannot advance a claim to hold on to the post on the specious ground that since under the rules applicable at the time of his ad-hoc promotion he was eligible, he cannot be reverted by reason of the rules framed and/or amended subsequently and applicable at the time of making regular promotion where under he is rendered ineligible. In the next place, the reversion of an ad-hoc appointee on account of the application of the extent Rules when the question of his regular promotion arises does not amount to retroactive operation of the rules. When the question of regular promotion to the posts of Superintending Engineers falls for consideration, the State Government will have to apply the extent rules, that is to say, the recruitment rules then in force. Since the Amendment Rules now hold the field, those rules (unless further amendments/fresh enactment are made meanwhile) will apply to determine the eligibility for promotion. The Amendment Rules are, under such circumstances, applied prospectively and not retrospectively because what is applied is the law in force as at that day. Merely because the effect of such application or operation of the Amendment Rules is the reversion of the ad-hoc appointees to the lower posts, it cannot be said that the rules are applied retrospectively. The rule against retrospective operation is not necessarily and in all cases attracted when the statute is applied to the fact situation as found on the day of its application It is settled law that the rule against retrospective construction is not attracted to a statute merely because apart of the requisites for its action is drawn from a time antecedent to its passing If that were not so, every statute will be presumed to apply only to persons born and things coming into existence after its enactment or operation. Such application of the rule may well result in virtual nullification of a large number of statutes. 8. The learned counsel for the petitioners, however, relied upon the decision of the Supreme Court in Y.V. Rangaiah and others v. J. Sreenivasa Rao and others, [1933 Lab IC 1240]. The decision is clearly distinguishable. In that case under the rules which were in existence at the material time, a list of approved candidates was required to be prepared in the prescribed manner by the appointing authority or any other authority empowered under the rules in that behalf in the month of September every year so as to be in force until the list of approved candidates for the succeeding year was prepared. There were administrative directions for the prompt preparation of panels in addition to the provisions made in the rules. The list of candidates in that case was required to be prepared as on September 1, 1976. However, it was not prepared till 1977. Meanwhile, by an amendment of the rules, the eligibility of certain categories to be promoted was done away with and promotional avenue was provided to a limited category of persons designated therein. The grievance of the petitioners in that case was that by delaying the preparation of list of approved candidates till after the rules were amended, their chances for consideration for appointment to the higher posts were adversely affected. It is against the background of the aforesaid facts that the Supreme Court held that under the old rules a panel had to be prepared every year in September and, accordingly, a panel should have been prepared m the year 1976 and that transfer or promotion to the higher post ought to have been made out of that panel. If timely action had been taken, the petitioners would not have been deprived of their right to be considered for promotion. Under the circumstances, it was held that the vacancies which occurred prior to the amended rules would be governed by the old rules and not by the amended rules. We see no parallel in the two cases. There is no rule requiring the preparation of panel within a specified time limit in the case in hand and no corresponding right accruing to persons eligible to be considered for inclusion in such panel on the basis of the extent eligibility qualifications. We see no parallel in the two cases. There is no rule requiring the preparation of panel within a specified time limit in the case in hand and no corresponding right accruing to persons eligible to be considered for inclusion in such panel on the basis of the extent eligibility qualifications. The decision in Rangaiahs case is, therefore, not applicable on the facts and in the circumstances of the present case. 9. No other point was urged. 10. Since we see no merit in this writ petition, it is summarily rejected. Petition dismissed.