In this case, Principal CIT having granted approval under Section 151 in a mechanical manner without applying his mind to the fact that the AO has sought approval for reopening the assessee’s assessment under Section 147(b) which has been omitted from the statute with effect from 1st April, 1989, the entire proceeding is vitiated and, therefore the same is quashed.  (AY. 2010-11 to 2013-14)