Tax deduction for eligible infrastructure businesses: full deduction for designated assessment years subject to statutory conditions. Section 80IA grants a deduction for profits of an eligible business engaged in specified infrastructure and related activities, allowing one hundred per cent deduction of such profits for a prescribed number of consecutive assessment years chosen within statutory windows. Eligibility depends on ownership, commencement dates, and contractual arrangements with government/statutory bodies; exclusions apply for undertakings formed by splitting up or by transfer of previously used machinery subject to exceptions. Computation treats the eligible business as a separate source, requires market-value adjustments for intra-assessee transfers, mandates audit reports as a precondition for deduction, and empowers adjustments where related-party arrangements distort ordinary profits.