In November 2012, when the city was in the throes of its worst smog spell in recent years, PM2.5 levels were consistently over 500 mg/cu m over several places.
“Beijing undertook several measures to control its air pollution levels during the Beijing Olympics in 2008 but the city is still prone to smog. More recently, it has decided to implement a lottery system for private cars which it hopes will keep a check on the rising number of vehicles,” said Anumita Roychowdhury, associate director at the Centre for Science and Environment.
Experts say that smaller the particulate matter, the more likely it is to affect human health. Between PM10 and PM2.5, the thicker particles are most likely to be natural while smaller ones are a result of activities such as combustion. This is why, claim environmentalists, vehicles are considered a major contributor to PM2.5 levels.
The two most likely reasons for high levels of PM2.5 at present are vehicular emissions and biomass burning.
Realizing the urgent need to tackle the city’s deteriorating air quality, Delhi’s environment department, with the help of other agencies, has drawn up a master plan. However, while it is still to be cleared by the cabinet, all good intentions are being wasted. The city’s biggest worry is its fleet of over 74 lakh vehicles to which about 1,700 are added each day.
Source: TOI (15 Jan, pg.3)