Section 44(a) in The Building Regulation in Respect of Lands Covered by the Calcutta Thika Tenancy (Acquisition and Regulation) Act, 1981
(a)For purpose of ventilation, every room in a masonry building or permanent structure shall have window and doors, opening directly into the external air or into an open verandah, having opening not less than 10 per cent of the floor area of rooms.
