In India, air pollution is widespread in urban areas where vehicles are the major contributors and in a few other areas which have a high concentration of industries and thermal power plants. Vehicular emissions are of particular concern since these are ground level sources and thus, have the maximum impact on the general population. The number of motor vehicles has increased from about 3 lakh in 1951 to 67 crore in 2003. In 2003, personal transport vehicles (two-wheeled vehicles and cars only) constituted about 80% of the total number of registered vehicles thus, contributing significantly to total air pollution load.
India is one of the ten most industrialised nations of the world. But this status has brought with it unwanted and unanticipated consequences such as unplanned urbanisation, pollution and the risk of accidents. The CPCB(Central Pollution Control Board) has identified 17 categories of industries (large and medium scale) as significantly polluting.