Increasing number of Vehicle is indicator of progress and prosperity of country but at the same time they are major threat to the environment in terms of pollution. Exhaust gases from the vehicle are pollutants and harmful for environment.
Pollutants are mainly:
CO- Carbon Mono Oxide
To control this pollution, we have BS norms [Bharat Stage ] in India which is equivalent to Euro Norms. These norms are different for petrol and diesel engines, 2W,3W and 4W. These norms are set by Central Pollution Control Board [CPCB] of India.
According to BS norms vehicle should not emit the pollutants more than the specific level [BS-I, II, III, IV]. To achieve the norms, Vehicle Manufacturers design the vehicle accordingly and get the approval from ARAI.