August 15, 2012
Air pollution in cities is rising at an alarming rate, new data from the World Health Organisation has revealed, particularly in emerging economies like India, where pollutants harm human health and hastening glacier melt.
Indian cities have some of the highest concentrations of particulate pollution, with as many as 14 cities among the worst 30, Bloomberg reported.
China, which has been plagued by air pollution, has improved its air quality since 2011 and now has only five cities in the top 30.
Noxious smog is spreading across the Ganga and Indus river basins, with Peshawar in Pakistan and Dhaka in Bangladesh also amongst the worst cities. Larger soot particles from regions also combine and get deposited on the ice in the Himalayas, accelerating glacier melt.
Fast growing cities in Saudi Arabia and Iran are also on the list of most-polluted urban areas with the highest levels of PM 2.5, tiny airborne particles, spewed out by cars factories and coal power stations that can lodge in the lungs or enter the bloodstream.
Global air pollution levels rose as much as 8% in the five years between 2008 and 2013, according to the database released on 12 May. Cities in poorer regions are suffering the most. All the 300 plus cities in middle- and low-income countries reported alarming rise, often five times beyond safety limits.
In Indian cities levels of larger PM10 particles (mostly dust, sand and soot) is also severe. These particles deflect heat and make urban areas warmer, contributing to climate change in lower altitudes. India has eight cities among the world’s worst 30 for PM 10 levels.
Very high levels of air pollution are “catastrophic for health”, Annette Pruss-Ustun, a co-author of the WHO study, told the Financial Times. Air pollution causes more than 3 million premature deaths worldwide every year, according to WHO, which on May 12 released the latest data on levels of particulate matter in 3,000 cities in 103 countries.
As urban air quality declines, the risk of stroke, heart disease, lung cancer and chronic and acute respiratory diseases, including asthma, increases for the people who live in them, the organisation said.
After Zabol in Iran, Gwalior and Allahabad in India are most polluted cities in the world. Patna and Raipur come in at sixth and seventh.
“This indicates air pollution is now a national crisis and needs strict and aggressive nation-wide action across all cities of India,” Anumita Roychowdhury, executive director at Centre for Science and Environment, said in a statement. It is worrying that cities outside India’s main urban centres are becoming more polluted, the Delhi-based think-tank said.
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Small ray of hope
Delhi’s air quality has improved since it was ranked the world’s most polluted city in the WHO’s 2014 global database. The India’s capital city was ranked eleventh this year.
The annual average PM 2.5 levels in Delhi have fallen by 20% since 2013. “Air policy action has started kicking in – with an environment compensation charge on trucks, action against other sources. We are responding to action but the levels are still very high in the city, it only shows that action has to be sustained to meet clean targets,” Roychowdhury told the Times of India.