Section 158(1) in The Mumbai Municipal Corporation Act, 1888
(1)When any building or land is let to two' or more persons holding in severally, the Commissioner may, for the purpose of assessing such building or land to the property taxes, either treat the whole thereof as one property, or, with the written consent of the owner of such building or land, treat each several holding therein or any two or more of such several holdings together, or each floor or flat, as a separate property.[* * * *] [Sub-sections (2) and (3) were deleted by Maharashtra 10 of 1998, Section 91.]