DELHI IS no longer the world’s most polluted city, says WHO. The national Capital is now the 11th most polluted city in the world, based on average annual PM 2.5 readings of 3,000 cities in 100 countries, according to the WHO’s latest urban air quality database for 2016.
Released on Thursday, the database shows that the annual PM 2.5 levels for Delhi were down from 153 micrograms per cubic metre in the WHO’s 2014 report to 122 micrograms per cubic metre.
The 2014 report was based on 2010 data while the latest report includes data from 2012, 2013 and a part of 2014 for India, a year before the new AAP government took charge in Delhi. As for other global cities, the data spans a period of 2008-2013, depending on the numbers available from those locations. The report states that global urban air pollution levels increased by eight per cent, despite improvements in some regions.
The latest PM 2.5 level rankings show Iran’s Zabol topping the list with 217 micrograms per cubic metre followed by Gwalior with 176 and Allahabad with 170. Patna at sixth place (149) and Raipur on seventh spot (144) are the other Indian cities in the top 10. In total, the top 20 global cities with highest PM 2.5 levels includes 10 Indian cities, including Kanpur, Ludhiana and Firozabad.
The PM 2.5 top 10 list also includes Saudi Arabia’s Riyadh (156) and Al Jubail, and two cities from China, Xingtai (128) and Baoding (126).
Among cities with highest PM 10 levels, Nigeria’s Onishta tops with an annual mean of 594 micrograms per cubic metre, followed by Peshawar at 540 micrograms per cubic metre. Delhi is at 25th position, with an annual level of 229 micrograms per cubic metre, based on data from 2012, according to the WHO.
Gwalior, with an annual average of 329 micrograms per cubic metre, is at tenth and the only Indian city on the top ten list of those with highest PM 10 levels.
PM 2.5 and PM 10 refer mostly to particles of dust, smoke and gaseous pollutants under 2.5 microns and 10 microns, respectively, in size — a strand of human hair is between 50 and 70 microns thick.
WHO’s air quality guidelines state that by reducing particulate matter (PM10) from 70 to 20 micrograms per cubic metre, air pollution-related deaths could be reduced by roughly 15 per cent. WHO safe limits for annual mean of PM 2.5 and PM 10 levels are 10 and 20 micrograms per cubic metre, respectively.
The 2014 report had placed Delhi under the scanner with an investigative series by The Indian Express in March-April 2015 exposing how in spite of numerous studies and alarm bells at repeated intervals, political inaction and the administration’s apathy set in motion a public health disaster in the making.
This January 1, Delhi’s AAP government, which came to power with a full term in February 2015, rolled out its odd-even vehicle rationing scheme — implemented in two 15-day spells so far — to control vehicular pollution.
During most of the WHO study period, the capital was under the Congress government led by Sheila Dikshit who lost power in December 2013. Following a 49-day reign by the previous AAP government that ended on February 16, 2014, Delhi was under President’s rule until elections were held in early 2015, when AAP claimed a decisive victory.
Nada Osseiran from the WHO’s department of public health, environmental and social determinants of health told The Indian Express that the latest report ranked cities according to annual aggregates of PM 10 and PM 2.5 — the same as WHO’s 2011 and 2014 analysis.
Dr Sophie Germy, a co-author of the WHO report, told The Indian Express over phone that the stress in the latest, upgraded report — the 2014 report had analysed pollution levels in only 1,400 cities — was on PM 2.5 levels.
“We have stressed on PM 2.5 because it is the pollutant which is of most health interest globally. We have analysed annual rather than 24-hour averages or real-time air quality, because we wanted to understand exposure levels over long term and see its effects. We are trying to see if these findings can be linked to the global disease burden,” said Dr Germy.
According to WHO, the 2016 report had five times more access to PM 2.5 data globally than the 2014 report. “This is due to improved monitoring, more cities have started monitoring this critical pollutant,” said Dr Germy.
Asked about Delhi’s success in reducing PM 2.5 levels, Dr Germy said, “I think India needs to be congratulated for its intensive monitoring of air quality, in metros and now tier-2 and tier-3 cities. Delhi, in particular, has done a lot of things to reduce PM 2.5 levels. The main source of PM 2.5 in India is fuel burning and vehicles… in particular, cars. I think on both accounts Delhi has recognised these sources as a problem and taken steps to control it.”
Dr Germy, however, pointed out that the data was not “immediate”. “Most of the India data is from 2012-2013, and partly from 2014. So it is not the immediate real-time government data put out everyday. To capture the long term effects of pollution, we have taken time to analyse annual data which is why it is not immediate updated data,” said Dr Germy.
Asked if other Indian cities, which figure among the highest global contributors to PM 2.5 and PM 10, need to replicate steps taken by Delhi, Dr Germy said, “A lot more needs to be done in India, and some steps need to be replicated. But one has to understand that even in some of the high- income cities, particulate matter continues to remain a problem despite intensive monitoring and steps to control pollution.”
Among the other findings of the 2016 WHO report are:
* Urban air pollution levels were lowest in high-income countries, with lower levels most prevalent in Europe, the Americas, and the Western Pacific Region.
* Highest urban air pollution levels were experienced in low-and middle-income countries in WHO’s Eastern Mediterranean and South-East Asia Regions, with annual mean levels often exceeding 5-10 times WHO limits, followed by low-income cities in the Western Pacific Region.
* In the Eastern Mediterranean and South-East Asia Regions, and low-income countries in the Western Pacific Region, levels of urban air pollution increased by more than 5 per cent in more than two-thirds of the cities.
* More than half of the monitored cities in high-income countries and more than one-third in low and middle-income countries reduced air pollution levels by more than 5 per cent in five years.