Section 22(2) in The U.P. Harijan and Social Welfare Gazetted Officers Service Rules, 1991
(2)The seniority inter se of persons appointed directly on the result of any one selection, shall be the same as determined by the Commission :Provided that a candidate recruited directly may lose his seniority if he fails to join without valid reasons when vacancy is offered to him. The decision of the appointing authority has to the validity of reasons shall be final.
