4. Letter dated 08.09.2004 referred to in para 3 above shows that vide G.O.Ms.No.364, Forest and R&D (For.III) dated 20.05.1978 issued under Section 28 of the Act total area of 29.81 Sq.kms or 2981.68 Ha, which includes the area leased out to the petitioner, was notified on Siwaram (Crocodile)Wildlife Sanctuary. As per Section 27 of the Act when an area is notified as a sanctuary no person other than a public servant on duty, or a person permitted by the Chief Wildlife Warden or the authorized Officer to reside within the limits of the sanctuary, or a person who has any right over immoveable property within the limits of the sanctuary, and a person passing through the sanctuary along a public highway; and the dependents of the above mentioned persons shall enter or reside in the sanctuary, except under, and in accordance with, the conditions of a permit granted under Section 28 of the Act. Section 28(A) lays down as the Chief Wildlife Warden may, on application, grant, a permit to any person to enter or reside in a sanctuary for investigation or study of wildlife and purposes ancillary or incidental thereto, or for photography or for scientific research, or tourism or for transaction of lawful business with any person residing in the sanctuary. In view thereof it is clear that quarrying of sand in an area, which is notified as a Wildlife sanctuary, that too without the permission from the wildlife Warden, is not permitted. Petitioner obviously was permitted to quarry sand for the year 2002-2003, due to lack of knowledge on the part of respondents or otherwise. It is well known that there cannot be any estoppel against a statute. So the fact that petitioner was permitted to