the Central Pollution Control Board (cpcb), India's apex pollution monitoring body, has decided to initiate monitoring particles less than 2.5 micron in size (pm2.5) in the ambient air of ten critically polluted cities from 2005. It has also proposed to bring ten more cities under this scanner every year after 2005. The cities will be prioritised on the basis of their violation of air quality standards for other pollutants. pm 2.5 has been associated with premature mortality and other serious health effects but its threat has not received due acknowledgement in the country.

Many studies have found very high levels of pm 2.5 in Indian metros. In many cities, the 24-hourly levels of these particles exceed the United States Environmental Protection Agency's (usepa) standard of 65 microgramme per cubic metre (