Section 26(1) in The Group 'D' Employees Service (U.P.) Rules, 1985
(1)Except as hereinafter provided the seniority of persons in any category of post shall be determined from the date of the order of substantive appointment and if two or more persons are appointed together, by the order in which their names are arranged in the appointment order :Provided that if the appointment order specified a particular back date with effect from which a person is substantively appointed, that date, will be deemed to be the date of order of substantive appointment and, in other case, it will mean the date of issue of the order.
