Section 2(h) in The Supreme Court Judges (Salaries And Conditions Of Service) Act, 1958
(h)“service for pension” includes―(i)actual service;(ii)time spent by a Judge of a High Court in attending the sittings of the Supreme Court as an ad hoc Judge under article 127 of the Constitution, if he is subsequently appointed as a Judge:(iii)the amount, actually taken, of each period of leave on full allowances at a rate equal to the monthly rate of the salary;
