Sulphur dioxide gas is produced when coal and diesel are burned. It's a gas that's both suffocating and destructive. Furthermore, petrol engines emit nitrogen oxides in the form of gaseous oxides. Acid rain is formed when sulphur and nitrogen oxides dissolve in rainwater and produce acids. It is extremely destructive to crops, structures, and soil. CNG (Compressed Natural Gas) is replacing diesel and petrol as automotive fuels since CNG emits hazardous pollutants in very small proportions. In comparison to traditional fuels, it emits a minimal amount of nitrogen dioxide, carbon dioxide, and sulphur dioxide. As a result, CNG is a more environmentally friendly fuel.