Deadly New Delhi Air Pollution Keeps Getting Worse

At certain times of year, some immense cities in the world become cesspools of extreme air pollution, putting the lives of millions of people in danger.

Extreme air pollution in India this past week. Photo by Arushree
Fadnavis./Reuters

In recent days, New Delhi, India has probably topped them all. The pollution was so thick, so dangerous, that you couldn't measure it.

A widely used air qualilty index measures ground level ozone, particulates, carbon monoxide, sulfer dioxide and nitrogen dioxide.  If the index is at 50 or lower, the air is clean and great to breath.

Up to 300, the air is a bit iffy - unhealthy for people with underlying health issues or other sensitivities, but the rest of us can probably manage, though with some potential health effects. If you get over 300, the air is downright dangerous for everybody.

We don't know how high the air quality index got in New Delhi, because the measuring devices only go to 999. I imagine the pollution levels were at least four times higher than what is considered dangerous for everybody.

 Here's how Time magazine describes what this is like:

"By one estimate, breathing Delhi's air for one day has the health impacts of smoking at least 25 cigarettes. Although Delhi typically experiences marked increases in air pollution around Novermber, this year's pollution prompted Delhi's Chief Minister, Arvind Kejriwal to call the city a 'gas chamber.'"

Time says New Delhi's experience with air pollution is part of a global trend that is causing roughly 7 million premature deaths annually.

Inversions, in which warm air traps cooler air beneath it, is the root meteorological cause of these pollution episodes. That warm air aloft acts as a lid so that pollutants can't escape and blow away. As cars, trucks, agricultural fires, factories and everything else loft stuff into the air, it just accumulates under this "lid," with toxic results.

In New Delhi's case, it started with an annual celebration called Diwali, in which lots of people set of fireworks. Those add a lot of smoke to the air.

This is also the time of year that farmers in land surrounding New Delhi to set fires in fields to clear land for the next round of crops.  Add to it the millions of cars, trucks, factories and scooter and you get a real disaster.

By the way, we here in Vermont are not immune from pollution problems caused by inversions.  These inversions often happen in the winter.  That can trap pollutants from things like cars and wood stove smoke in our Green Mountain valleys, elevating pollution levels.

The area around Rutland, for instance, is shaped like a bowl, and is sometimes subject to wintertime air pollution alerts. Of course, and thankfully, Rutland will never get as bad as New Delhi.