Section 411(4)(a) in The Calcutta Municipal Corporation Act, 1980
(a)Notwithstanding anything contained in the foregoing sub-sections, the Municipal Commissioner may, forthwith or with such notice as he thinks fit, demolish, repair or secure or cause to the demolished, repaired or secured, any such wall or building or thing affixed thereto, on the report of the Chief Municipal Architect and Town Planner, certifying that such demolition, repair or securing of the building, wall or thing is necessary for the safety of the public or the inmates of the building.