Dismissing the appeal the appeal of the revenue the Court held that , the satisfaction and approval of the Chief Commissioner or the Commissioner under section 151(1) was a sine qua non before issuance of a notice under section148 by the Assessing Officer, who might be of the rank of an Income-tax Officer or Assistant Commissioner or Deputy Commissioner, but when such notice was to be issued after the expiry of four years period of limitation, the sanction of the Chief Commissioner was a precondition. The proviso to section 151(1) , when it referred to an Assessing Officer, could also mean not merely an Assessing Officer below the rank of an Assistant Commissioner and a Deputy Commissioner but also all Assessing Officers.( AY. 1996 -97)