Vehicular emission has become a major source of air pollution in many cities in India. There is a rapid growth in vehicular population in India. The number of cars has been doubling in every seven years for the past 30 years (UNEP,2002 ). During 1997 to 2000 the number of vehicles has increased from 37.3 million to 48.3 million (MoST).
Growth in number of vehicles (in million)
Source MoST
Vehicles are one of the major source of air pollution in urban centres of the country. Diesel vehicles emit more PM and NOx than petrol vehicles. However, CO and HC emissions are more from petrol vehicles. Though, improvement of vehicular emission norms have led to reduction of emissions from newer vehicles but smoke emitted from older vehicles is still a concern, especially in absence of an efficient inspection and maintenance system. Many cities have banned the entry of older commercial vehicles in specific zone where air quality is a major concern.
Private vehicles are growing at a rapid pace. Reasons that could be attributed to this are growth in incomes, availability of loan facilities, and absence of a god public transport system. Some cities are coming up with plans of METROs and Bus based mass transit systems. Funding under the JNNURM program is proving beneficial for cities to improve their public transport infrastructure.
Growth in vehicles not only lead to air pollution but also cause severe congestion which is the major cause of wastage of fuel and time on roads in cities. Lack of parking spaces is another concern. Many cities are coming up with bye-passes to avoid the transiting traffic within the city limits.
Fuel efficiency standards are also being enforced on the vehicles to reduce their fuel consumption and thereby reduce the emissions from tail-pipe.
Vehicles not only emit fro their tail-pipe but also cause re-suspension of road dust when they move over the roads. His is also an emerging source of air pollution which is considered. Major causes of high silt content on the roads are low quality of roads, irregular maintenance and improper cleaning.