Why is CNG considered better fuel than LPG?

CNG refers to Compressed Natural Gas which consists of methane whereas Liquefied Petroleum Gas is a mixture of propane & butane. Carbon dioxide and water vapour are the only byproducts when CNG is burnt. In LPG, three or four carbon bonds are present thus releasing carbon dioxide in excess along with other harmful gases. Moreover, CNG is lighter gas as compared to LPG. So in case of leakage, CNG gets mixed with atmosphere nut LPG will get oxidized and can cause an accident. Therefore CNG is considered better fuel than LPG.