Section 67(2)(a) in West Bengal Municipal (Employees' Service) Rules, 2010
(a)when such an employee is undergoing treatment for-(i)Cancer or cardiac ailments in a recognised hospital or nursing home; or who receives treatment at his residence under a specialist recognised as such by the State Government and produces a certificate signed by that Specialist to the effect that he is under his treatment and that he has reasonable chances of recovery on the expiry of the leave recommended.(ii)Leprosy in a recognised Leprosy Institution by a Medical Officer of Health or a Specialist in leprosy recognised as such by the State Government. He may, subject to such conditions as the Local Body may by a general or special order prescribe, be granted extra-ordinary leave for a period not exceeding 180 days.