Compressed Natural Gas (CNG) is a clean-burning alternative fuel made by compressing natural gas, primarily composed of methane. It is stored at high pressure in special tanks, making it suitable for use in vehicles and as an energy source. CNG is often used in buses, trucks, and other fleet vehicles due to its lower emissions compared to gasoline or diesel. CNG is considered an environmentally friendly option because it produces fewer pollutants and greenhouse gases when burned. It is also more cost-effective than traditional fuels in many regions, contributing to its growing popularity in the transportation sector and among energy providers.