Section 39(8) in Tamil Nadu Combined Development and Building Rules, 2019
(8)Basement Floor. - (a) The height of basement floor shall not exceed 1.2 meters above ground level and the headroom shall be minimum 2.4 meters.(b)In cases where more than one basement is proposed for parking and incidental uses, sufficient provision for lighting and ventilation and also for protection from fire to the satisfaction of Directorate of Fire and Rescue Services shall be made.(c)During the construction of the basement floor, it shall be the sole responsibility of the Building Permit holder to ensure that the building or structure in the adjoining sites are not weakened or damaged.(d)The basement shall be permitted below the ground and beyond the building lines at ground level subject to a clear minimum front setback space of 4.5m and side and rear setback of 3m, subject to non habitable uses and provision for mechanical ventilation and all safety provisions and drainage. However, it is essential that the basement top slab below the external circulation at ground level should be designed for firefighting vehicular loads
