Section 660(b) in Police Regulations, Bengal , 1943
(b)In the rank of Sub-Inspector there is in the Unarmed Police -(i)a casualty reserve calculated at 14 per cent, of the sanctioned number of Deputy Superintendents, Indian Inspectors and Sub-Inspectors in the district, and intended to provide for vacancies caused by leave granted to such officers and not by any other casualties, and(ii)a reserve for replacing probationers under practical training.
