S. 147 : Reassessment-After the expiry of four years-No failure on the part of the assessee to disclose fully and truly all material facts necessary for the assessment-Reopening of the completed assessment on the basis of same set of facts and on mere change of opinion based on an internal audit of the Revenue’s functioning held illegal and quashed-Sanction is given without application of mind-Reassessment is quashed. [S. 148, 151, Art. 226]