Section 7(2)(e) in The Special Rules for the Mulit-storeyed and Public Buildings, 1974
(e)Width of any exit shall not be less than 100 cm. and shall be determined for the total number of occupants as specified in the following table. The unit of exit width for measuring the capacity of exits shall be 25 cms. A clear width of 25 cm. shall be counted as an additional half and any width less than 25 cm. shall not be counted for calculating width :-