Section 251(2) in Chennai City Municipal Corporation Act, 1919
(2)If the [standing committee] [Substituted for 'licence appeals committee' by Tamil Nadu Act 22 of 1971.] does not, within thirty days from the receipt of such written request, determine whether such permission should be granted or not, such-permission shall be deemed to have been granted; and the applicant may proceed to execute the work but not so as to contravene any of the provisions of this Act or any rules or by-laws made under this Act.