[jabl]

When I was visiting India roughly a decade ago, I was told that it was very common for gas stations to bulk gasoline with kerosine. Apparently kerosine is heavily subsidized by the state as it's used for cooking by poor people, so it's a lot cheaper than gasoline.

The problem with this is that it reduces the octane rating of the fuel, and as a result cars in India are apparently commonly detuned in order to avoid knocking when running on low octane gas.

That being said, bulking up gasoline with kerosine sounds like a less bad idea than using water, as I'd guess the water phase separates from the gasoline.