This working paper details the differences in fuel specifications for commercial gasoline and diesel fuels in India and the EU, and assesses potential air pollutant emission impacts of these differences. The proposed Bharat Stage (BS) VI regulation for on-road vehicles in India includes contains both emission standards for new vehicles as well as specifications for reference and commercial gasoline and diesel fuels. These specifications define requirements for physical properties and chemical composition of the fuels, and are meant to ensure that commercial fuels are of sufficient quality and compatible with engine and emission control technologies that will be required to meet BS VI emission standards.