In the middle of this month, air pollution in Beijing was so bad that the Chinese government issued urgent health warnings and closed four major highways, prompting the panicked buying of air filters and the donning of face masks. However, in New Delhi, where pea-soup smog created what was by some measurements even more dangerous air, there were few signs of alarm in the country’s boisterous news media, or on its effervescent Twittersphere.
Despite Beijing’s widespread reputation as having some of the most polluted air of any major city in the world, an examination of daily pollution figures collected from both cities suggests that New Delhi’s air is more laden with dangerous small particles of pollution more often than Beijing’s. Lately, a very bad air day in Beijing is about an average one in New Delhi.
The US embassy in Beijing sent out warnings in the middle of this month, when a measure of harmful fine particulate matter known as PM2.5 for the first time this year went above 500, in the upper reaches of the measurement scale. This refers to particulate matter less than 2.5 micrometers in diameter, which are believed to pose the greatest health risk because they penetrate deeply into the lungs.
However, for the first three weeks of this year, New Delhi’s average daily peak reading of fine particulate matter from Punjabi Bagh, a monitor whose readings are often below those of other city and independent monitors, was 473, more than twice as high as the same average in Beijing of 227. By the time Beijing had its first pollution breach past 500 on the night of Jan. 15, Delhi had already had eight such days. Indeed, only once in three weeks did New Delhi’s daily peak value of fine particles fall below 300, a level more than 12 times the exposure limit recommended by the WHO.
“It’s always puzzled me that the focus is always on China and not India,” said Angel Hsu, director of the environmental performance measurement program at the Yale Center for Environmental Law and Policy. “China has realized that it can’t hide behind its usual opacity, whereas India gets no pressure to release better data. So there simply isn’t good public data on India like there is for China.”
Experts have long known that India’s air is among the worst in the world. A recent analysis by Yale researchers found that seven of the 10 countries with the worst air pollution exposures are in South Asia and evidence is mounting that Indians pay a higher price for air pollution than almost anyone in the world.
A recent study showed that Indians have the world’s weakest lungs, with far less capacity than Chinese lungs. Researchers are beginning to suspect that India’s unusual mix of polluted air, poor sanitation and contaminated water may make the country among the most dangerous in the world for lungs.
India has the world’s highest death rate because of chronic respiratory diseases and it has more deaths from asthma than any other nation, according to the WHO. A recent study found that half of all visits to doctors in India are for respiratory problems, according to Sundeep Salvi, director of the Chest Research Foundation in Pune.
Clean Air Asia, an advocacy group, found that another common measure of pollution known as PM10, for particulate matter less than 10 micrometers in diameter, averaged 117 in Beijing in a six-month period in 2011. In New Delhi, the Center for Science and Environment used government data and found that an average measure of PM10 in 2011 was 281, nearly 2.5 times higher.