Section 52(16)(iv) in Tamil Nadu Combined Development and Building Rules, 2019
(iv)in cases where the ventilation is derived through open to sky. the dimensions of the open to sky need to be 1.5m x 2.5m. This will apply to kitchens and store rooms but not to lavatories and bath rooms which shall have windows or ventilators of not less than 0.5sq.m. abutting such open space