Margin-based state tax exemption for used motor vehicles applies, limited to supplier margin and subject to input tax credit exclusion. Exempts state tax on specified intra-state supplies of old and used motor vehicles by applying a margin-based taxation method: tax is limited to the amount calculated on the supplier's margin with prescribed rates by vehicle category. Vehicle classification follows the Motor Vehicles Act; negative margins are ignored. Where depreciation under income-tax law was claimed, margin equals sale consideration minus depreciated value; otherwise margin equals selling price minus purchase price. The exemption does not apply if the supplier has availed input tax credit, CENVAT, VAT credit or other input tax on the goods.