Section 171(8)(b) in The Calcutta Municipal Corporation Act, 1980
(b)land or building acquired, constructed, purchased or owned by the Government or any of the statutory bodies mentioned [in clause (a) for] [Words, letter and brackets substituted by W.B. Act 32 of 1983.] any Government approved scheme for the purpose of subsidised housing for persons belonging to low income group or industrial workers and comprising of tenements let out to such persons on a monthly rent shall be twenty-one per cent, of the annual value of such land or building determined under this Chapter;