Section 390(1)(h) in Kolkata Municipal Corporation Act, 1980
(h)to convert into a stall, shop, office, warehouse or godown, workshop, factory or garage any building not originally constructed for use as such, or to convert any building constructed for such purpose, by sub-division or addition, in greater or lesser number of such stalls, shops, offices, warehouses or god-downs, workshops, factories or garages;