Fuel, will be taxed heavily, All State Governments, Central Government have become dependent on taxes on Petrols and Diesels for many years now. Plus refining costs are going up with BS IV and capital investment to be made for BS VI fuel. Going through PSU Oil companies websites and other information on various global oil sites, it seems that while Petrol and Diesel come from crude, they have independent market where Diesel is generally costlier. The prices seem to vary a bit differently for both these fuels.
But some States Like Punjab, Maharastra, Karnataka, Kerala, Telegnana, West Bengal, UP really charge exorbitant VAT rates. Petrol in Pondicherry costs 7 Rs lesser than what it is AP, KN and Bengaluru. Anyone on a holiday from Bengaluru to Puducherry should consider bring a few Petrol cans along.