The Full form of CNG is Compressed Natural Gas. CNG mainly consist of methane gas which produces engine power after it is mixed with air and fed into an engine’s combustion chamber. CNG can be used as a substitute for Petrol, Diesel and Propane/LPG. It is effective to control air pollution because it produces fewer undesirable gases in comparison to other petroleum products. So it is more environment-friendly than other fuel products. It is also safer than its other substitutes in the case of the spill because CNG is lighter than air and disperses quickly when released. The properties of CNG is that it is colorless, tasteless, odorless, non-toxic, non-corrosive, 40% lighter than air and high ignition temperature. The advantages of CNG are i.e. it is cheaper than its other substitutes e.g. Petrol and Diesel which are used to run buses, cars and other automobiles, the maintenance cost for the vehicles that run on CNG is low as compared to the vehicles run on Petrol and Diesel, it is more environment-friendly because it emits less undesirable and harmful gases than other substitutes, it enhances the life of lubricant oils because it does not contaminate and dilute the crankcase oil, it provides a high auto-ignition temperature of 540 degree Celsius or more.