What is isobutanol, which govt plans to blend into diesel?

Isobutanol is a higher alcohol produced from ethanol or biomass and is widely regarded as a next-generation biofuel. It blends well with diesel, offers higher energy density and produces lower emissions than many conventional biofuels. Union Minister Nitin Gadkari said the government plans to allow blending of up to 15% isobutanol into diesel to cut reliance on imported fossil fuels.