The section gives you a standard, not a form. Section 251(2) bars enhancement unless the appellant has had "a reasonable opportunity of showing cause against such enhancement", and the words "such enhancement" carry the requirement of specificity — you cannot show cause against a proposal you have not been told. What the section does not say, and what I could find no decision saying, is that the notice must contain the arithmetic.
The operative words are short. Sub-section (2) provides that the appellate authority "shall not enhance an assessment or a penalty or reduce the amount of refund unless the appellant has had a reasonable opportunity of showing cause against such enhancement or reduction". The departmental page I fetched still carries the pre-1988 designation "Appellate Assistant Commissioner"; a commentary reproducing the current text names the Commissioner (Appeals), and now also the Joint Commissioner (Appeals).
Read the words in order. The bar is absolute — "shall not enhance ... unless". The opportunity has to be "reasonable", which is the ordinary natural-justice standard and takes its content from the facts. And it has to be an opportunity of showing cause against "such enhancement", not against enhancement in the abstract. That last phrase is where the argument about the adequacy of the notice lives: an opportunity to answer a proposal is not an opportunity at all unless the proposal has been identified.
That gives you a sequence of objections to a thin notice, in descending order of strength. First, jurisdiction — is the item one the Assessing Officer considered at all, expressly or by necessary implication? If not, the Shapoorji Pallonji Mistry and Rai Bahadur Hardutroy line, and the Full Bench in Sardari Lal, say the route is reassessment or revision, not enhancement, and the notice fails whatever it says. Second, identification — does the notice tell you which receipt, which disallowance, which year, and on what material? Third, quantification — does it tell you how much. The first two are supported by authority in this library. The third is the point the brief flags, and I could not close it.
What I did find, and record with a warning, is a 2026 Delhi High Court decision reported on a single digest, Sahara India Commercial Corporation Ltd. v. ACIT, where a disallowance was enhanced from about Rs 11.05 crore to about Rs 16.74 crore without any notice under s.251(2). The Court is reported as holding that it is obligatory on the appellate authority to issue a notice and provide an opportunity of hearing to show cause against the proposed enhancement, that issuance of notice means the intention to take an action in explicit terms, and that unless an assessee is put to notice about the proposed action he cannot be expected to defend his cause. On that reporting it is a decision about the absence of a notice rather than about the contents of one, and the phrase "in explicit terms" is the nearest thing to a specificity standard I could find. I could not corroborate the decision on a second source and it is not written up as an entry in this library; verify it before citing it.
So the honest answer is: argue specificity from the words "such enhancement" and from the general natural-justice standard, and be prepared for the department to say that a notice identifying the item is enough and that the computation can be worked out in the order. Whether that is right is not settled by anything I could reach.
Enhancement is where a first appeal turns into a loss, and the reply to the notice is usually written on the merits alone. The jurisdictional objection and the adequacy objection both have to be taken in writing, before the order, or the Tribunal is being asked to entertain them cold. The adequacy point is also worth taking because it is cheap: if the notice does not identify the proposal, asking for particulars costs nothing and either produces them or produces a record that they were never given.
How wide are the first appellate authority's powers when it disposes of an appeal?
The assessing officer accepted my method of accounting. Can the first appellate authority reject it for the first time in my own appeal and enhance the assessment?
The first appellate authority has enhanced my assessment using items the Assessing Officer never looked at. Can it do that, or has it gone beyond its jurisdiction?
Can the CIT(A) use the enhancement power to tax a source of income the Assessing Officer never examined?
Can an appellate authority under the Income-tax Act throw out an appeal because the appellant did not turn up?
Can the first appellate authority tax a source of income the officer never looked at?
Can you raise a ground before the CIT(A) that you never raised before the officer?
The assessing officer ignored my partition claim and assessed the family anyway. If the Tribunal finds that illegal, can it simply cancel the assessment and stop there?
Every page in this library links to what it was written from, so you can check it rather than take our word for it.
