Infrastructure deduction allows consecutive-year tax holiday for eligible undertakings providing specified infrastructure, subject to audit and conditions. Deduction under Section 80-IA grants a tax concession for profits of undertakings that develop, operate or maintain specified infrastructure facilities, telecom services started by the prescribed cutoff, SEZs, industrial parks and power generation/distribution meeting prescribed conditions. Eligibility requires ownership and development agreements where specified; the concession is available for a consecutive block of assessment years chosen within a statutory window, with phased treatment for telecom services. Claims require audited accounts and Form No. 10CCB, separate financial statements for each undertaking, and deductions are capped at profits and barred where amalgamation or demerger transfers the undertaking.