As far as I know petroleum and alcohol are kept out of the GST as both these products provide major revenue.Therefore the states are to lose a lot of income if these two are to be brought under the GST. Nevertheless both these products are heavily taxed that;s why bringing them under the GST would cause serious losses in incomes for the countries providing them and in serious increase in the prices we pay for them. So if someone is looking how to stop drinking alcohol this thread could be a great stimulant in doing so.