The approval was granted in a mechanical manner and without application of mind. Reassessment notice and order is quashed. As per CBDT Circular No. 19/2019, dated 14-08-2019, it is a mandatory requirement that the Document Identification Number (DIN) must be quoted on the body of the assessment order and demand notice at the time of issuance. A subsequent generation of DIN (either on the same day or the next day) and its intimation to the assessee via a separate communication does not satisfy the conditions laid down in paragraphs 3 and 4 of the circular. Since the requirement of quoting the DIN on the original assessment order and demand notice was not met, they are unsustainable in law.  (AY. 2013-14, 2014-15)