<h1>Agricultural extension project notification under Form 21 requires approval, compliance, renewal, and revocation safeguards.</h1> Form 21 is the notification instrument issued by the Central Board of Direct Taxes for an approved Agricultural Extension Project under Section 47(1)(a) of the Income-tax Act, 2025 read with Rule 37. It is issued after examination of Form 20, records the project particulars, approved tax years, expected expenditure, and notification conditions, and is authenticated by signature and Official Gazette publication. The notification remains valid for up to three Tax Years, is subject to compliance and renewal requirements, and may be revoked for cessation, non-genuine activities, or breach of approval conditions.