ORDER

(The petitioners and respondents 4, 5 and 6 are members of the Punjab Service of Engineers (Class I) (the Service) in the Irrigation Department of the State of Punjab. The respondents are members of the Scheduled Castes whereas the petitioners belong to the general category. The conditions of service of the members of the Service are governed by the Rules called the Punjab Service of Engineers Class I P. W. D.(I. B.) Rules, 1964 (the Rules). The Punjab Government by the instructions dated May 4, 1974 provided reservations for the Scheduled Castes and Backward Classes in promotions to and within Class I and II services under the State Government. It was laid down under the said instructions that 16 percent of the posts to be filled by promotion were to be reserved for members of the Scheduled Castes and Backward Classes (14 percent for the Scheduled Caste and 2 per cent for the Backward Classes) subject to the conditions that the persons to be considered must possess the minimum necesary qualifications and they should have satisfactory record of service . the instructions further provided as under :

"(1) In a lot of 100 vacancies occurring from time to time, those falling at ser