S. 151 : Reassessment-Sanction for issue of notice-After expiry of three years-It would be Principal Chief Commissioner who would be liable to be recognized as being competent authority- Sanction accorded by Principal Commissioner for reassessment under section 148A is not valid-Reassessment notice and consequential order was quashed. [S.148, 148A(b), 148A(d), Art. 226]