Section 2(6) in West Bengal Municipal (Building) Rules, 2007
(6)"alteration" means change from one occupancy to another, or a structural change, such as an addition to the area or height, or the removal of part of a building, or any change to the structure, such as, the construction of, cutting into or removal of any wall, partition, column, beam, joist, floor or other support, or a change to the fixture or equipment;
