Section 390(1) in Kolkata Municipal Corporation Act, 1980
(1)The expression "to erect a building" means(a)to erect a new building on any site, whether previously built upon or not;(b)to re-erect(i)any building of which more than one-half of the cubical contents above the level of plinth have been pulled down, burnt or destroyed, or(ii)any building of which more than one-half of the superficial area of the external walls above the levels of plinth has been pulled down, or(iii)any frame-building of which more than half of the number of posts or beams in the external walls have been pulled down;(c)to convert into a dwelling house any building or any part of a building not originally constructed for human habitation or, if originally constructed for human habitation, subsequently appropriated for any other purpose;(d)to convert into more than one dwelling house a building originally constructed as one dwelling house only;(e)to convert into a place of religious worship or a sacred building any place or building not originally constructed for such purpose;(f)to roof or cover an open space between walls or buildings to the extent of the structure formed by the roofing or covering of such space;(g)to convert two or more tenement in a building into a greater or lesser number of such tenement;(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;(i)to convert a building, which when originally constructed was legally exempt from the operation of any building regulations, contained in this Act, or under any rules or regulations made under this Act, or contained in any other law in force for the time being, into a building which, had it been originally erected in its converted form, would have been subject to such building regulations;(j)to convert into or use as a dwelling house any building which has been discontinued as or appropriated for any purpose other than a dwelling house;(k)to make any addition to a building;(l)to close permanently any door or window in any external wall;(m)to remove or reconstruct the principal staircase or to alter its position;