CNG used in automobiles to check pollution, mainly consists of

Detailed Solution:

The correct answer is “CH4”.

Compressed natural gas (CNG) used in automobiles to check pollution mainly consists of methane (CH4).

CNG is a clear, odor-less, non-corrosive fuel that is extracted from natural gas wells or produced through processes like biogas production or synthetic gas generation. It is compressed to less than 1% of the volume it occupies at standard atmospheric pressure.