Constitution of India , Art.16— Promotion - Change in scheme - Retrospective effect - Employees of co-operative society - Service rules providing for promotion on basis of five yearly assessment - Revised scale with new career assessment scheme for promotion introduced retrospectively - Plea of employee that his vested right of consideration for promotion could not be defeated by retrospective amendment - Not entertained. The respondent was appointed in 1982 as Scientist S in ICAR a registered society. Relavant service rules at the time of appointment of the respondent provided for assessment, promotion etc. on the basis of a five yearly assessment. The respondent should have become eligible for grant of next higher grade of Scientist S-II in 1987. Subsequently revised pay scales of Scientists were introduced replacing the old Scheme of assessment by new Career Assessment Scheme of the UGC w.e.f. January 1, 1986. Old Scheme ceased to operate after Dec. 31, 1985. The respondent gave his option to be covered under the new Scheme with the rider that the option was subject to the clarification in regard to his career advancement after consideration of the five yearly assessment which was in vogue in the year 1987 when he became eligible for consideration for the next higher grade. The respondent was promoted w.e.f. 1990 under the new scheme. The respondent plead....