Section 3(3)(a) in The Chennai City Corporation Building Rules, 1972
(a)Every application for permission to construct or reconstruct a building shall be accompanied by plans of the building, the elevations and the sections, neatly and accurately drawn or reproduced in a clear and intelligible manner in blue or other photographic print or drawing paper or tracing cloth to a scale of not less than one centimetre to one metre except where the building is so extensive as to render a smaller scale necessary when the scale of one centimetre to two metres may be used.