Delhi might be the most polluted city in the world but the government insists that the Capital’s air is not as bad as that of Beijing -- contrary to the real time data available in public domain.
The air-quality monitoring wing of the ministry of earth sciences has claimed that Delhi’s particulate matter 2.5 pollution levels never crossed 350 microgram per cubic metre (m/cum) while for Beijing, it was higher than 500 microgram and even reached 650 microgram.
The data is based on information collected from the ministry’s nine monitoring stations and doesn’t take into account records of the Delhi Pollution Control Committee and Central Pollution Control Board.
HT Edit: Choking to death: Delhi's air is dirtier than Beijing’s
Had it done that, it would have found that pollution levels on January 24 at Shahdara and Mandir Marg were alarming -– more than 900m/cum during evening rush hour. On Tuesday, the levels dropped to average between 230 m/cum and 430 m/cum at places such as Mandir Marg, Anand Vihar and Punjabi Bagh.
The World Health Organisation, which last year termed polluted air as a carcinogen, says PM2.5 at 10 m/cum is safe. India’s safety mark is 60 microgram.
HT on Wednesday did another check on PM2.5 data and Delhi again beat Beijing flat. While Chinese’s capital recorded a pollution level of 275 m/cum, Delhi University’s PM 2.5 level was 500 m/cum and ITO’s 360 at 7pm.
Moreover, the daily PM2.5 levels available for Beijing for 2013 showed that these varied from less than 50 m/cum to as high as 400 m/cum but largely remained below 250 m/cum, Centre for Science and Environment (CSE) said.
But for Delhi, where air pollution is higher in winter than in other seasons, the daily average for November 2013 and January 2014 period shows that pollution has hovered around 240 m/cum -- almost four times higher than the Indian standard. It even went as high as 575 m/cum, CSE said. Even at its highest, Beijing’s winter level didn’t go beyond 400 m/cum.READ: Pollution control plan in limbo as Delhi gasps for breath
The results of Yale University Environment Performance Index (EPI) giving Delhi the worst ranking may differ from India’s stations monitoring air pollution. Yale findings are more reliable as the data is collected from independent sources and environmental satellites fitted with sensors.
Station monitoring provides correct exposure level only at a particular place, while satellite-based measurements are more universal, helping draw a clearer comparison between cities.
Read: How air and water pollution plagues Indian cities
Particles smaller than 2.5 microns in diameter (PM2.5 in shorthand) are fine enough to lodge deep in human lung and blood tissue and cause diseases ranging from stroke to lung cancer, the Yale study said.