Identify a cleaner fuel which is used in vehicles from the given options.
CNG
The fuels which leave a lesser amount of toxic substances and undesirable harmful exhausts after combustion are cleaner fuels. Compressed Natural Gas (CNG) is a cleaner vehicle fuel than kerosene, petrol and diesel and it is also safer than other fuels in the event of spills because natural gas is lighter than air and disperses quickly when released.