Section 36(3) in New Town Kolkata Planning Area (Building) Rules, 2014
(3)Outer walls of a basement may be extended below ground level upto a maximum of 5.00 m from the property line only for one level of basement for use of parking only. In case of more than one basement is required, the depth of the basement shall not exceed the distance between boundary line and outer periphery of basement in all sides;
