Forms › Specified Businesses & Projects › Form 18

Form 18 — Application for notification of an affordable housing project as specified business

Compiled — pending CBDT Appendix III cross-check C · Specified Businesses & Projects
Replaces old Form 3CN. Under the Income-tax Act, 2025, this compliance now uses Form 18.
New form numberForm 18
Old form number3CN
Act 2025 referenceSpecified business
CategoryC · Specified Businesses & Projects
Applies fromTax Year 2026-27 (from 1 April 2026)

What is Form 18?

Form 18 is the Income-tax Act, 2025 form titled “Application for notification of an affordable housing project as specified business”. It replaces the earlier Form 3CN used under the Income-tax Act, 1961 (and the Income-tax Rules, 1962). The purpose of the form is unchanged — the number and format have been updated under the new law.

It falls under the Specified Businesses & Projects category, and applies to Tax Year 2026-27 (AY 2026-27) onwards, i.e. from 1 April 2026.

A fuller plain-language explainer for Form 18, reviewed by our Chartered Accountants, is being added.

Transitional rule — which form applies?

⚠️ Which form applies depends on the tax year the compliance relates to, not the calendar date you file. Proceedings for tax years beginning before 1 April 2026 (assessments, appeals, TDS for transactions up to 31 March 2026, and Section 89 relief for those years) continue on the old forms.

Frequently asked questions

What is the new form for Form 3CN?

Under the Income-tax Act, 2025, old Form 3CN is replaced by Form 18 — Application for notification of an affordable housing project as specified business. It applies to Tax Year 2026-27 onwards.

From when does Form 18 apply?

It applies to Tax Year 2026-27 (AY 2026-27) onwards, i.e. from 1 April 2026. Compliance relating to earlier tax years continues on the old forms.

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This directory is compiled from official CBDT / incometax.gov.in sources and reputable references, and is being reconciled against the Gazette-notified Income-tax Rules, 2026 (Appendix III). Forms marked “compiled” are pending that final cross-check. This is general information, not tax advice.