23. (1) Notwithstanding anything contained in any other law for the time being in force or in any agreement, no person shall, without the previous sanction of the Authority, construct any building or excavate any tank within the area to which this Ordinance extends. (2) The Authorised Officer may, on an application made for the purpose in such manner and in such form and accompanied by such fee as may be prescribed, sanction the construction of a building or excavation of a tank subject to such conditions as the Authority may deem fit. (3) If in the opinion of the Authorised Officer any of the conditions subject to which the sanction under sub-section (2) was granted has been contravened, he may cancel the sanction. (4) The provisions of sub-section (1) shall not apply to a case of normal repairs to an existing building.