Section 294(1)(e) in The Calcutta Municipal Corporation Act, 1980
(e)to provide and set up all such appliances and fittings as may appear to the Municipal Commissioner to be necessary for the purpose of gathering and receiving the waste water from floors and galleries of buildings when they are washed and conveying the same through spouts by down-take pipe so as to prevent such waste water from discharging directly on streets or inside any lower portion of the premises;