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Scientist Joshua Apte monitors pollution on his laptop as he travels in an auto-rickshaw during rush-hour traffic in New Delhi. Photo: AP

New Delhi's pollution levels go from world's worst to even worse

Contamination levels of world's most polluted city up to 700pc higher near roads, study finds

AP

The three-wheeled rickshaw lurched through New Delhi's commuter-clogged streets with an American scientist and several air pollution monitors in the back seat. Car horns blared. A scrappy scooter buzzed by belching black smoke from its tailpipe. One of the monitors spiked.

Joshua Apte has alarming findings for anyone who spends time on or near the roads in this city of 25 million. The numbers are far worse than the ones that have already led the World Health Organisation to rank New Delhi as the world's most polluted city.

Drivers often spend hours in New Delhi traffic. Photo: Reuters
Average pollution levels were 50 per cent to 700 per cent higher on the road than urban background readings, including official ambient air pollution measures, according to research by Apte and his partners at the University of California, Berkeley, and the Indian Institute of Technology in New Delhi.

"And you have to keep in mind that the concentrations at urban background sites, where these official monitors are, are already very high," he said.

The point is particularly important for New Delhi residents, about half of whom live within 300 metres of a major road.

"Official air quality monitors tend to be located away from roads, on top of buildings, and that's not where most people spend most of their time," Apte said. "Most people spend a lot of time in traffic in India… one, two, three hours a day."

Outdoor air pollution kills millions worldwide every year, according to the WHO, including more than 627,000 in India. One of the biggest culprits in India is vehicular traffic: Car ownership in the country of 1.2 billion grew from 20 million in 1991 to 140 million in 2011, and is expected to reach 400 million by 2030.

Unchecked, today's vehicle trends in India could lead to a three-fold increase in levels of PM 2.5 by 2030 - the tiny particulate matter believed to cause the most damage to human health - according to a study this month by The Energy and Resources Institute in New Delhi.

Still, few Indian cities have air quality monitors. New Delhi officially has 11, though experts say the readings can be erratic and the reporting opaque. The city reports several key pollutants and this month launched an air quality index.

Apte said that such indices represented vague urban background readings and couldn't help residents understand exactly what risks they faced.

What ordinary people really want to know are answers to questions like, "'Should I be taking a walk outside in this neighbourhood right now?' ... 'Is it safe for my child to be playing cricket on the field here?'," he said.

Apte's approach to gathering his data involved twice-daily rush-hour open-air rickshaw drives. He also took readings from inside cars with the windows rolled up, and from a rooftop monitor that stood for ambient air quality readings.

He found rush-hour levels of PM 2.5 were about 50 per cent higher than in ambient air. The monitor shot up to eight times the ambient reading when lumbering vehicles emitting black smoke rolled by.

This article appeared in the South China Morning Post print edition as: New Delhi pollution: worst to worse
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