Section 11(4) in Tamil Nadu District Municipalities (Hill Stations) Building Rules, 1993
(4)Where a building wholly or partly intended for human habitation, is not separated from the adjoining buildings on two sides, an open space of not less than one-fourth of the area of the site shall be left as space open to the sky.Explanation. - An open courtyard may be included in the calculation of the area left as vacant space open to the sky.
