SEZ deduction under Section 10AA permits phased tax relief for export profits subject to eligibility, filing and reinvestment conditions. Deduction for SEZ units permits phased tax relief on export profits-100% for five years, 50% for next five, and reinvestment reserve based deduction for a further five-subject to eligibility conditions including non splitting/reconstruction limits, limits on second hand machinery, receipt of export proceeds in convertible foreign exchange within prescribed periods, filing of return with Form 56F CA certificate, audited books, and utilization rules for the SEZ Reinvestment Reserve to avoid deeming and taxation.