Margin-based GST exemption on used motor vehicles; specified rates apply and ITC-availed supplies excluded from the benefit. Exempts State GST on intra-state supplies of specified used motor vehicles by taxing only the supplier's margin at prescribed rates by vehicle category. Margin is measured as consideration minus depreciated value where depreciation was claimed, or as selling price minus purchase price otherwise; negative margins are ignored. The exemption is inapplicable if the supplier availed input tax credit, CENVAT, VAT credit, or other tax credits on the goods.