A DIN is a computer-generated number the CBDT requires on income-tax communications so that every notice or order has an audit trail. Under CBDT Circular 19/2019 a communication issued outside the permitted exceptions without a DIN was to be treated as invalid and deemed never to have been issued; that circular has since been superseded by Circular 4/2026 dated 31 March 2026, and the Finance Act 2026 has inserted a curative provision that blunts DIN challenges retrospectively.
A DIN is not a statutory creature. It comes from an administrative direction of the CBDT under section 119, which binds income-tax authorities. Circular No. 19/2019 dated 14 August 2019 required, from 1 October 2019, that every communication relating to assessment, appeals, orders, exemptions, enquiry and investigation carry a computer-generated Document Identification Number.
The circular allowed manual communication without a DIN only in listed exceptional circumstances, and only with the prior written approval of the Chief Commissioner or Director General: where technical difficulties prevented generation or quoting of the DIN; where the officer was outside the office in the discharge of official duties; where the PAN sat with a non-jurisdictional Assessing Officer pending migration; where proceedings other than those under sections 131 and 133 were initiated and no PAN was available; and where the functionality to issue the communication was not available in the system. The manual communication had to state on its face that it was issuing without a DIN, giving the reason and the approval reference.
The teeth were in the consequence clause. A communication not in conformity with the circular was to be "treated as invalid and shall be deemed to have never been issued". Communications issued under the first three exceptions had to be regularised within fifteen working days by uploading them, generating a DIN and intimating that DIN to the assessee.
The Delhi High Court in CIT (International Taxation) v. Brandix Mauritius Holdings Ltd held that an assessment order without a DIN was non est in law, and that section 292B — which saves proceedings from being invalid for a mistake, defect or omission — could not cure it, because a communication deemed never to have been issued is not a defective communication at all. The court proceeded on the footing that CBDT circulars under section 119 bind the revenue.
The position has now moved twice. First, Circular No. 4/2026 dated 31 March 2026 replaces Circular 19/2019. It keeps the core requirement — a computer-generated DIN on notices, letters, orders, draft orders and summons — but relaxes the mechanics: the DIN can be quoted once in the document, the covering email or an attachment rather than on every page; approval for an exceptional communication can be obtained within fifteen days; the approving authority is graded (Joint Commissioner or Additional Director for lower-ranked officers, Chief Commissioner or Director General for higher ones); and the exceptional communication must still be uploaded with a DIN within fifteen working days.
Second, and more significantly, the Finance Act 2026 (Act No. 4 of 2026) inserted section 292BA into the Income-tax Act, 1961, with retrospective effect from 1 October 2019. It provides that no assessment shall be invalid on the ground of any mistake, defect or omission in quoting a computer-generated DIN if the assessment order is referenced by such number in any manner. The equivalent provision for the new regime sits in section 522 of the Income-tax Act, 2025.
In practice this splits the argument into two. A defect in how the DIN was quoted — wrong placement, omission on the face of the order where the DIN exists on the system and the order is referenced by it — is now curable. A case where no DIN was ever generated, and the order is not referenced by any DIN at all, is still arguably outside the cure, because there is nothing to reference. That distinction is where the fight has moved.
A DIN point is a jurisdictional-style objection that can dispose of an assessment without touching the merits, so it is worth checking on every order and notice before you draft anything else. After the Finance Act 2026 amendment you can no longer win on a cosmetic quoting defect, so the reply has to show that no DIN exists on the system at all, not merely that it is missing from the page. Where the department relies on an exception, the burden is on it to show the approval and the regularisation within fifteen working days.
Can interest under ss.234A, 234B and 234C be waived?
The company I represent amalgamated years ago, the department knew about it, and the assessment order still came in the old company's name. Is that order void, or can the department call it a curable slip?
The AO says I sold below market value and wants to tax the difference. Can he do that?
A Board circular supports my reading of the section. Can I hold the Tribunal or the High Court to it, and can a circular settle what a provision means?
Is an assessment on an amalgamated company always void?
The notice names a company that has already merged into another. Does taking part in the proceedings fix that?
The reassessment notice was issued in the name of my old private limited company, which had already been converted into an LLP and dissolved. I am told that makes the notice void. Is that always right?
A Board circular gives me a benefit the section itself does not clearly allow. Can the Assessing Officer ignore it and apply the strict law instead?
Every page in this library links to what it was written from, so you can check it rather than take our word for it.