S. 153A: Assessment-Search-Approval should not be rubber-stamping and mere ritual formality and should not suffer from lack of application of mind-The Addl. CIT also granted approval under s. 1 on the very same day, in the other 12 cases-The approving authority has not applied his mind and granted the approval in a mechanical and hasty manner-Approval suffers from perversity and impropriety-The approval is invalid in the eyes of law, and consequently the assessment order is also invalid.[S. 153D]