Input Tax Credit: the six conditions, the blocked list, and the 30-Nov clock that makes it lapse

Most ITC problems aren't about whether you're entitled to a credit — they're about whether you can still prove it, on time, against a moving statutory clock. This is the full map: the conditions that make a claim valid, the categories that are blocked no matter what, the two reversal rules that get confused with each other, and the deadline that turns a missed credit into a permanent loss.

ITC is conditional, not automatic

Input Tax Credit is the mechanism that keeps GST a tax on value added rather than a cascading one: the tax your supplier charged you on a purchase becomes a credit you can set off against the tax you owe on your own sales. But holding a valid invoice and having paid your supplier is necessary, not sufficient. Section 16(2) of the CGST Act lays out a set of conditions that must all be satisfied before a claimed credit is actually yours to keep — and every one of them can independently disqualify a credit that looks fine on your books.

The six conditions under Section 16(2)

Read together, clauses (a), (b), (aa), (ba), (c) and (d) of Section 16(2) are what a reconciliation team is actually checking every month, even if nobody calls it that:

Clause (b) is worth calling out on its own: possessing a valid invoice (a) and actually receiving the goods or services (b) are two separate, independently-disqualifying conditions. An invoice with no underlying movement of goods or services is the fact pattern behind most fake/bogus-invoicing ITC denials and demands — invoice possession alone never substitutes for it.

The practical consequence is that GSTR-2B is not a courtesy statement — under Section 16(2)(aa) it is the legal precondition for the claim. If an invoice isn't in your 2B, reconciling to it before filing GSTR-3B is not a best practice, it's the law. That flow now runs through the Invoice Management System: your Accept/Reject/Pending action (or inaction, which counts as acceptance) is what determines whether a record lands in 2B at all — see the full mechanics in GSTR-2B, IMS & hard-locking.

Section 17(5): credit that's blocked regardless of the six conditions

Even a credit that clears every Section 16(2) condition can still be disallowed outright under Section 17(5), which lists categories of "blocked credit" — ineligible by category, not by paperwork. Three of the categories that cause the most confusion in reconciliation:

• Sec 17(5)(c) — works contract for immovable property. ITC on works-contract services for constructing immovable property is blocked, except where the service is itself an input for supplying further works-contract service.
• Sec 17(5)(d) — construction on own account. ITC is blocked on goods or services received for constructing immovable property (other than plant and machinery) on your own account. This is the provision at the centre of the Safari Retreats litigation — and it's worth stating precisely because it's widely misreported: the Finance Act 2025 retrospectively substituted "plant and machinery" for "plant or machinery" in the text, with effect from 1 July 2017, which nullifies the reading the Supreme Court had allowed. ITC on construction of immovable property on own account stays blocked — do not claim it on the strength of the earlier Safari Retreats outcome.
• Sec 17(5)(h) — losses, write-offs, gifts. ITC is blocked on goods lost, stolen, destroyed, written off, or disposed of as gifts or free samples.

These three are illustrative, not exhaustive — Section 17(5) covers other categories too (motor vehicles, club memberships, and more), each with its own carve-outs. Treat any construction, write-off or gift-related input as ineligible at source and verify against the full clause before claiming it.

Rule 37 vs Rule 37A: the two reversal clocks that get confused

Once a credit is validly claimed, it isn't necessarily safe — two separate rules can force a reversal, and they trigger on opposite failures. Mixing them up means reversing a credit for the wrong reason, or missing the deadline on the right one.

Rule 37 is about your payables discipline. Rule 37A is about your supplier's filing discipline — specifically GSTR-3B, not GSTR-1. A supplier who filed GSTR-1 but never remitted the tax through GSTR-3B is exactly the Section 16(2)(c) failure Rule 37A exists to reverse. And a third situation is neither: if a supplier hasn't filed GSTR-1 at all, the invoice never reaches your 2B in the first place, so there's nothing claimed and nothing to reverse — see what to do when a supplier hasn't filed GSTR-1 for that case specifically.

Both reversals carry interest at 18% per annum on the credit wrongly availed and utilised, computed from the date of utilisation, under Section 50(3) read with Rule 88B — another reason to catch these on a monthly cycle rather than at year-end.

Section 16(4): the 30 November clock that makes credit lapse for good

Section 16(4) sets an absolute outer limit: ITC for an invoice or debit note of a financial year cannot be taken after 30 November of the following year, or the date of filing the annual return, whichever is earlier. This is not a reversal-and-reclaim situation like Rule 37 or 37A — a credit that crosses this deadline unclaimed is gone permanently, with no re-availment path.

Common credit and the annual true-up

Where inputs, input services or capital goods are used partly for exempt supplies or non-business purposes, Rule 42 (inputs and input services) and Rule 43 (capital goods) require the credit to be reversed proportionately, with an annual true-up. Any business with mixed taxable/exempt turnover or non-business use needs to run this apportionment every period and reconcile it annually, not just at claim time.

Why this is a monthly reconciliation problem, not a filing-day one

Every condition above resolves to the same operational reality: a claimed credit is only as good as the invoice, the 2B entry, the supplier's filing status and the calendar, checked together — and checked before you file, because GSTR-3B's auto-populated fields are increasingly non-editable once filed. Doing that by hand across a few invoices a month is manageable. Doing it across hundreds of vendors, multiple GSTINs, a rolling 2B and a hard 30 November wall is painful to do manually — and a single missed line either lapses permanently or turns into a wrongly-availed credit carrying 18% interest.

Recoup reconciles every claimed credit against the invoice you hold, your GSTR-2B/IMS position and your payment status to the supplier — automatically flagging Rule 37 invoices approaching day 180, Rule 37A exposure from suppliers who filed GSTR-1 but not GSTR-3B, and unclaimed eligible credit as the 30 November deadline approaches, so nothing lapses because nobody was watching the calendar.

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