Compressed natural gas
Compressed natural gas (CNG) vehicles operate much like gasoline-powered vehicles with spark-ignited internal combustion engines.
The engine functions the same way as a gasoline engine. Natural gas is stored in a fuel tank, or cylinder, typically at the back
of the vehicle.Compared to diesel and even to petrol, natural gas creates far less nitrogen oxides (NOx) and particulate matter (PM) when combusted. The combustion process is also quieter. CNG is therefore a better 'urban' fuel than diesel. Lower CO2 emissions, both tailpipe and well-to-wheel.