Worst air pollution in the world: Beijing, Delhi, Ahwaz, and Ulaanbaatar.

Which City Has the Worst Air Pollution in the World?

Which City Has the Worst Air Pollution in the World?

Health and medicine explained.
March 5 2013 11:40 AM

Where Is the Worst Air in the World?

Beijing gets a lot of attention for its pollution, but it’s nowhere near the top of the list.

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Farther down the list are more cities in Iran, along with some in India, Pakistan, and Botswana, before Delhi appears in the 12th spot, with average particulate levels of 198 parts per million.

To Americans, Asia’s air pollution woes may seem a world away. But it is a small world. Pollution travels east along jet streams from Asia to the North American West Coast. Research indicates that nearly one-third of the soot in the San Francisco Bay Area blew over from Asia.

The most polluted region in the United States, according to the WHO’s air quality data, is in California’s Central Valley, where industrial and exhaust pollution gets trapped inside an expansive bowl of rock that’s home to farms, heavy industry, and millions of people. But the valley city of Bakersfield, America’s No. 1 air pollution hotspot, ranked just 276th in the WHO’s list, with an average PM10 count of 38 parts per million.


I’ve spent time in Los Angeles, and I lived for a year in the Central Valley. The ambient pollution in those places can be sickening. But it doesn’t compare to that in Delhi.

Here, it feels like I’m drawing tiny fibers deep into my respiratory system. They seem tangibly solid against my spongy insides.

Regulations such as the Clean Air Act and technological advances have helped scrub America’s air. That is not the case in many developing countries.

“We could easily have taken a cleaner pathway of development,” says India’s Rajendra Pachauri, who chairs the Intergovernmental Panel on Climate Change. He pointed out that cities such as Pittsburgh and London have recovered from terrible air pollution from when the United States and the United Kingdom were at earlier stages of development. “Unfortunately, we have not learned from those examples.”

The New York Times’ India Ink blog reported that air pollution was more than twice as bad in Delhi on Jan. 31 than it was in Beijing. There are 46 cities, in such countries as the United Arab Emirates, Saudi Arabia, Egypt, India, Mexico, and Nigeria, where average pollution levels exceed those of Beijing. Overall, India recently ranked last in a list of 132 countries surveyed for their air quality.

Most of the pollution that I inhale in Delhi comes from diesel-burning trucks and buses. Other aerial filth that enters my lungs broke away from gasoline as it combusted incompletely in cars and from natural gas burned by auto rickshaws.

Coal-fired power plants and agricultural burning take a toll. As do makeshift campfires that line the streets at night during the winter, where everything from leaf litter and cow dung to rubber motorcycle saddles are burned for warmth.

It’s not that officials here don’t care. Efforts to cut pollution from vehicles in Delhi in the late 1990s and early 2000s, by taking such steps as switching auto rickshaws over to natural gas and requiring annual vehicle inspections, helped clear the air. But as the city’s wealth grows, it is experiencing an explosion in the number of cars and other vehicles on its roads, pushing air pollution levels back up again. The Indian Express newspaper recently reported that Delhi’s environment department is mulling a suite of efforts to tackle the problem anew, such as promoting public transit, jacking up parking fees, shuttering coal-fired power plants, and more harshly penalizing those who break pollution rules.

But as is the case in so many other cities in developing countries throughout Asia, economic progress and the clamor for trade, travel, and newfound luxuries are proving no match for incipient government programs that aim to protect people from bad air.

After just six months in India, I’m growing accustomed to occasional fits of coughing and hacking. I hold American and Australian passports, and even as a freelance journalist I’m wealthy by local standards, making it easy to leave Delhi whenever I am ready.

But for a substantial portion of the planet’s population, some of them Chinese but many of them living in countries where pollution woes go little noticed by Western journalists, there would seem to be little hope of gulping at the fresh air that so many people in other parts of the world take for granted.