S. 151 : Reassessment-Sanction for issue of notice-Amount involved is more than Rs. 50 lakhs-Approval has to be obtained from Principal Chief Commissioner or Chief Commissioner as defined under section 151(ii)-Approval was obtained from Principal Commissioner in terms of section 151(i) and no approval was obtained before issuance of reopening notice in terms of provision of section 151(ii)-Reopening notice was quashed and set aside. [S. 148,149, 151(1), 151(ii), Art. 226]