Margin scheme tax exemption for used motor vehicle sales reduces state tax rates; excludes supplies with input tax credit. State tax is exempted on intra state supplies of specified old and used motor vehicles by applying a margin based calculation: tax is levied only on the supplier's margin at prescribed rates (9% or 6% per vehicle category). Margin equals selling price minus purchase price, or consideration minus depreciated value where depreciation was claimed, with negative margins ignored. The exemption is inapplicable if the supplier has availed input tax credit, CENVAT or VAT input credit. Vehicle specifications and categories are defined and the exemption takes effect from 25 January 2018.