Section 37(2)(b) in West Bengal Municipal (Employees' Service) Rules, 2010
(b)all his seniors, except those unfit for promotion to the particular higher grade, available nave been promoted to that grade. He may, with the approval of the State Government, also be allowed to draw such officiating pay in the next higher grade, which he would have drawn from time to time had he been on duty other than duty under clause (10) (d) of sub-rule (1) of rule 4.