Concessional duty for EOU DTA sales permitted within export-linked entitlement, subject to positive NFE and SION compliance. Export-oriented units (other than gem and jewellery) may, upon achieving positive Net Foreign Exchange, sell goods and specified secondary materials in the domestic tariff area under Paragraph 6.8(a) of the FTP at a concessional duty equal to half the basic customs duty plus the additional duty under section 3; sales beyond entitlement attract full duties. Waste, scrap and by-products must meet SION norms and concessional clearance for such materials is available only if the unit is eligible under the FTP entitlement, with higher wastage reviewed by the Board of Approval on verified data.