S. 153A: Assessment-Search-Approval of prescribed authority-Approvals in 30 cases rushed through on same day Difficult to believe that Additional Commissioner considered all proposals and accompanying draft assessment orders within a few minutes or even a couple of hours-Approval need not resemble reasoned decision-But should reflect minimal application of mind-Absence of valid and prior approval vitiates assessment-Non-application of mind-Tribunal right in quashing assessments-Order of Tribunal affirmed-No substantial question of law. [S. 132,153D, 260A]