Govt hikes windfall tax on petrol, cuts duty on diesel. The government has hiked the windfall gains tax on petrol exports to ₹2.5 per litre from ₹0.5 per litre, effective immediately, according to the latest notification. Meanwhile, the duty on diesel exports has been cut to ₹8.5 per litre from ₹16 per litre. The windfall tax on aviation turbine fuel (ATF) exports remains unchanged.