Compressed natural gas, CNG, is natural gas under pressure which remains clear, odorless, and non-corrosive. CNG (methane stored at high pressure) can be used in place of gasoline (petrol), Diesel fuel and propane/LPG. CNG combustion produces fewer undesirable gases than the fuels mentioned above. It is safer than other fuels in the event of a spill, because natural gas is lighter than air and disperses quickly when released.