Where a rectification order under section 154 was issued without a Document Identification Number and was not covered by or regularised under the exceptions provided in CBDT Circular No. 19/2019, such order was invalid and deemed never to have been issued; subsequent communication purporting to allot DIN could not cure the defect and, accordingly, both the rectification order and subsequent communication were liable to be quashed. Where the Assessing Officer issued notice under section 154(3) on 20-6-2024 proposing rectification but purported to have passed the rectification order on 29-3-2024, the issuance of the subsequent notice itself demonstrated that the rectification order could not have been passed on the earlier date; the order was therefore inferred to be backdated and barred by limitation under section 154(7), besides having been passed without the mandatory opportunity of hearing, and was accordingly quashed.  Submission of revenue regarding alternative remedy was rejected, followed,  Whirlpool Corporation v. Registrar of Trade Marks, (1998) 8 SCC 1, (AY. 2005-06)