Section 21(1) in Tamil Nadu State Housing Board Act, 1961
(1)The Board shall establish a Housing Unit for the area Comprising (i) the City of Madras and (ii) places situated within twenty-five miles of the limits of the City of Madras by the name "The Madras Housing Unit"; and the Board may, with the approval of the Government, establish by resolution a Housing Unit for any other area for the efficient performance of its functions in that area.
