Section 250(3) in The Mumbai Municipal Corporation Act, 1888
(3)Provided also that clause (a) shall not be deemed to apply to any privy in existence when this Act comes into force, unless -(d)there is space available on the premises of the owner or occupier for the erection of a new privy conformably to the said clause; and(e)the existing privy can be removed and a new one erected as aforesaid without destroying any portion of a permanent building other than the existing privy.