The rapid growth of population and industry in India during the last two decades has resulted the need for adequate mass transport facilities for quick movement and materials. The diesel engine has always been a preferred prime mover for haulage of heavy loads due to its superior fuel economy.
In the last 15 years, there has been a rapid increase in the number of diesel vehicles. A majority of automotive diesel engine are rated at about 100 BHP and are almost exclusively used in city, buses and trucks. With the increasing number of diesel vehicles, the diesel smoke has come under severe criticism in India also, especially in the large cities.