Section 119(2) in Kolkata Municipal Corporation Building Rules, 2009
(2)Any chimney shall be built at least 0.9 m. above any roof:Provided that the top of any chimney shall not be below the top of any adjacent wall and in the case of a sloping roof, the top of the chimney shall not be less than 0.6 m. above the ridge of the roof in which the chimney penetrates.