By: Kamala Kelkar
A battle between India and China unfolded in the Indian and international media this week about which country had the world’s most polluted capital city.
According to a front-page report by the Hindustan Times, which was widely followed by Indian news channels, Delhi had surpassed Beijing to take the dubious honor.
Or had it?
Hindustan Times cited a new study by U.S.-based Yale and Columbia universities — a biennial report titled the “Environmental Performance Index,” or EPI, to substantiate their claims.
However, Angel Hsu, the lead author of the study told The Wall Street Journal in an email that EPI research was not based on city-specific findings and only concentrated on nationwide pollution by comparing the levels of pollutants less than 2.5 microns in diameter — scientifically called PM 2.5 — in the atmosphere.
“The EPI is a country ranking and does not compare cities,” Ms. Hsu wrote.
The reality is, Delhi does not maintain enough reliable data to make a fair comparison with other cities, according to an EPI statement issued late Wednesday. “New Delhi’s reporting is not as consistent or transparent, making direct comparison impossible,” the statement said.
An accurate comparison of air quality in any two cities requires data from consistently-calibrated ground stations. Beijing reports data on PM 2.5 concentration on an hourly basis over a publicly-accessible platform, according to EPI. There are several air monitoring stations throughout the Indian capital and at least two different government-funded sites that report their results. But one rarely works and the other makes an assessment based on 24-hour-averages.
To be sure, Delhi has a pollution problem. But a scientist here who monitors the capital’s air quality says that recent comparisons to Beijing made in both the Hindustan Times and the New York Times are speculative.
“The air quality in Delhi and in India is very bad,” said G. Beig, a program director at a research department under the Ministry of Earth Sciences. “But certainly it is not as bad as Beijing’s,” he added.
Mr. Beig’s department is the one that measures the air quality by taking in hourly information creating an average over a 24-hour-period. His site also makes forecasts based on weather and available data. He says based on their assessments, Delhi’s peaks at specific stations may be worse than Beijing’s PM 2.5 averages, but when comparing averages, Delhi’s are consistently less.
So what does the EPI report actually say about India?
It is not good news. India ranks last among the world’s 20 biggest economies in terms of air pollution levels, and along with China, has the highest average exposure to PM 2.5 in the world. PM 2.5 are toxic, microscopic particulates small enough to enter the lungs and pollute a person’s blood stream. Often, they are linked to severe health problems such as lung cancer.
By U.S. standards, PM 2.5 measuring more than 201 is classified as “very unhealthy,” and levels higher than 301 are considered “hazardous” to health. Pollution levels exceeding this, “would trigger health warnings of emergency conditions” according to a U.S. government body.
Some of the smoggiest days in New Delhi last month had PM 2.5 averages of 400,according to data collected by the Ministry of Earth Sciences. This had dropped to 131 on Thursday afternoon, real-time air monitors run by the Ministry of Earth Sciences showed.
The South Asian nation also ranks 155 out of 178 countries in terms of its global environmental performance, coming behind Indonesia at 112 and China at 118.
“Middle income countries such as Brazil India and China are still growing economically and see the steepest increase in emissions over the last decade,” the report said.
The Centre for Science and Environment, a New Delhi-based nonprofit, issued a statement Wednesday pointing out that Delhi has done far less than Beijing to address the problem.
Beijing controls the number of cars allowed to be sold in a year and has adopted a health alert system that sometimes closes large factories on particularly polluted days, among other progressive steps to tackle the problem, according to CSE.
Researchers from the Yale-Columbia study agreed. “New Delhi may or may not have dirtier air than Beijing, but it is clearly behind in how it makes air quality information available to its citizens,” they said in the EPI statement.