Section 395(1) in Kolkata Municipal Corporation Act, 1980
(1)Every person giving any notice of his intention to erect a building under section 393 shall specify the purpose for which such building is intended to be used :Provided that for any building, not more than one class of use, consistent with the occupancy or the use group within the meaning of sub-section (2) of section 390, shall be considered except in respect of the cases where, under this Act or any other law in force for the time being, mixed occupancies of specified nature may be permissible.
