Level of air pollution in Delhi
The ambient air quality is being monitored in 216 cities, towns and industrial areas all over the country including Delhi under the National Ambient Air Monitoring Programme (NAMP). The parameters which are monitored are Sulphur Dioxides (SO2), Nitrogen Dioxide (NO2) and Particulate Matter (PM10). The details on ambient air quality parameters monitored in Delhi from 2001 to 2010 are annexed. The changes in the air quality of Delhi before and after the introduction of Compressed Natural Gas (CNG) / Liquefied Petroleum Gas (LPG) indicate decline in Sulphur Dioxides (SO2) levels whereas the levels of Nitrogen Dioxide (NO2) and Particulate Matter (PM10) indicate increasing trends. The change in air quality of Delhi, however, is attributable to a number of different factors.