Section 66A(4) in The Mumbai Municipal Corporation Act, 1888
(4)The [Mayor] [This word was substituted for the words 'Mayor' or any member of the Mayor-in-council' by Maharashtra 27 of 1999, Section 20(d), (w.e.f. 23-4-1999)] shall not be bound to answer a question if in his opinion, it cannot be answered without detriment to the interests of the Corporation or if, it asks for information which has been communicated to him in confidence.]