Write a short note on CNG (Compressed Natural Gas)?

The CNG (Compressed Natural Gas) is used as a substitute to petrol and diesel in vehicles. Delhi Transport Corporation (DTC) has totally switched over to CNG where buses aas well as auto rickshaws run on CNG. It has reduced levels of pollution in the city. CNG is a cleaner fuel than diesel, used currently in many cities and long-distance transport across the country. It contains mostly methane, compressed to 80 atmospheres. CNG also works out cheaper (one-third) than diesel in long run because of stable price. Moreover, it is readily available, its carcinogenic potential is lesser, it cannot be adulterated and gives higher mileage i.e. 35-40 km per kg.