A tale of three cities: How pollution fight unites Delhi, Beijing and Zabol
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A tale of three cities: How pollution fight unites Delhi, Beijing and Zabol

Beyond the man-made, Delhi’s pollution is also the result of a quirk of nature – something that the residents of Beijing and Zabol know a thing or two about.

india Updated: Nov 13, 2017 09:16 IST
Joydeep Thakur and Sutirtho Patranobis
Joydeep Thakur and Sutirtho Patranobis
Hindustan Times, New Delhi/Beijing
Air Pollution,Delhi,Beijing
People wear protective masks at Rajpath as pollution level remained severe in the Capital on Sunday.(PTI)

Several meteorological factors combine with man-made emissions to aggravate Delhi’s pollution problem every winter, a phenomenon that experts say is common to some of the world’s most polluted cities, Beijing in China and Zabol in Iran.

Delhi’s air quality index (AQI), which measures the concentration of poisonous particulate matter in the air, hit the “severe” level on November 7 and has stayed in this dangerous zone since then. The AQI hit a peak of 486 on November 9, and even breached the maximum reading of 500 at some monitoring stations. Anything above 100 is considered unhealthy.

Though the levels of deadly particulate matter dropped on Friday, they started shooting up again from Saturday afternoon.

The thick haze of smoke that has enveloped the national capital has been attributed primarily to burning of crop residue in Punjab and Haryana and vehicular pollution in a city of 17 million people. Experts say that dust from West Asian countries, such as Saudi Arabia, Kuwait and Iraq, has also contributed.

“The pollutants were transported to Delhi and other parts of northwest India by strong-velocity high-altitude winds coming from west Asia. These, along with pollutants from stubble burning regions of Punjab and Haryana, pushed up the pollution levels in Delhi,” said Gufran Beig, project director of the System of Air Quality And Weather Forecasting And Research (SAFAR), a government agency linked with the ministry of earth sciences.

But, beyond the man-made, Delhi’s pollution is also the result of a quirk of nature – something that the residents of Beijing and Zabol know a thing or two about.

Every year, ahead of the onset of winter, Delhi’s air quality worsens because cooler surface air traps pollutants closer to the ground. In the absence of ground winds, these pollutants from construction activities fail to disperse into the atmosphere, a phenomenon known as inversion.

When high altitude winds bring in clouds of smoke from burning stubble farms in Punjab and Haryana, the entire city is trapped in a bubble of noxious air.

“While emissions from various sources had already pushed up the national Capital’s pollution level to the ‘very poor’ category since October, unfavourable meteorological conditions aggravated the situation,” A Sudhakar, member secretary of the Central Pollution Control Board, said. “This has resulted in a drastic rise in pollution levels as the city has become like a chamber with almost no outlets.”

This is a problem that the residents of Zabol, an eastern Iranian city, face every year. During summer, dust storms rage, bringing in pollutants from neighbouring Afghanistan and Pakistan. The city can experience up to 80 dust storms in a year that bring in loads of dust from neighbouring countries. The only way to fight back is to distribute anti-pollution masks to all its residents.

Beijing also suffers from similar problems. What crop-burning is to Delhi, the so-called “industrial rust belt” is to Beijing. There are thousands of factories around the Chinese capital and in its six neighbouring provinces and regions Tianjin, Hebei, Henan, Shanxi, Shandong and Inner Mongolia.

This December 20, 2016 photo shows commuters wearing masks on a polluted day in Beijing. (AFP File Photo)

“Wind patterns or air mass movements are an important reason (for pollution accumulation.) The current Delhi pollution is happening because of transfer of pollution from crop burning areas. Beijing pollution is from industrial rust belt areas,” said Lauri Myllyvirta, a Beijing-based energy analyst with environmental advocacy group Greenpeace.

In 2016, the World Health Organisation named Zabol the world’s most polluted city based on the level of PM2.5 – the ultrafine particles which sticks deep inside the lungs and takes the heaviest toll on human health. While Delhi ranked 11th, Beijing ranked 57th on the list.

While crop burning and weak winds make Delhi’s air bad in the colder months, the city’s topography contributes to particulate aerosol in summers that are marked by strong winds.

“Delhi has a variety of soil. The soil has degraded in several areas because of construction and development. They become loose, and get blown by wind easily. This adds to air pollution,” said CR Babu who heads the Centre for Environmental Management of Degraded Ecosystems at University of Delhi .

Farmer burning stubble on Sirhind road in Patiala on October 31. (Bharat Bhushan/HT Photo)

In summer, dust is also brought in to Delhi by storms from the north-west. These winds, western disturbances as they are called, pick up dust in large amounts from the desert-like north-western India and even west Asian and sub-Saharan countries.

To counter pollution, China and India have various measures in place. China has introduced a four-tier colour-coded system for air pollution, with red being the most serious, followed by orange, yellow and blue.

Delhi has woken up late but now has its Graded Response Action Plan – an emergency measure based on various categories of pollution, which is being implemented for the first time.

In China, the number of heavy pollution days (when the AQI is higher than 100) has dropped from 58 days in 2013 to 39 days in 2016. In Delhi, proper implementation will be needed to reverse the trend.

But the only long-term solution, experts say, is to cut down on burning fossil fuels. In China, for example, progress on air pollution control stalled in the region after a stimulus push started by the government in early 2016, leading to a temporary increase in output and prices of steel, cement and other products from highly polluting industries.

The plan now is to gradually curb polluting industries to begin with. It’s also said to be considering curbing the use of vehicles that use fossil fuels to amplify the fight against weather conditions by controlling man-made

First Published: Nov 13, 2017 08:25 IST