New Delhi: An Indian government agency on Thursday challenged a finding by the World Health Organization (WHO) that New Delhi is the most polluted city in the world, increasing the risk of heart and respiratory disease and cancer for residents.
Delhi’s annual mean of particulate matter (PM2.5) was 153 microgram per cubic metre compared with 56 microgram per cu. m in Beijing, the Chinese capital, according to WHO data. Other Indian cities such as Gwalior, Patna, Raipur and Ahmedabad also recorded high levels of particulate matter, above 100 microgram per cu. m.
WHO had overstated the pollution level in New Delhi, said a scientist at the Indian Institute of Tropical Meteorology, which functions under the ministry of earth sciences.
“The average yearly value of PM2.5 of Delhi ranges between 110-120 microgram per cu. m and WHO has overestimated it as 153 microgram per cu. m and Beijing average is underestimated,” said Gufran Beig, chief project scientist at the institute’s System of Air Quality Weather Forecasting and Research (SAFAR). “It should be noted that there is an ambiguity in years of comparison in WHO report for Delhi and Beijing data.”
A study by SAFAR published earlier this year had revealed that emissions from local pollution sources in Delhi had increased by 10% to 20% between 2010 (94.26 gigagrams) and 2014 (107.49 gigagrams). It said the increase was highly non-linear and steady and cannot lead to sudden extremes in pollution.
Data released by SAFAR for air pollution between 2010 and 2014 reveals that there had been no systematic increase or decrease in the level of PM2.5 in the past four years in Delhi, but the frequency of extreme pollution events was on the rise.
Still, there is cause for concern, especially about the increasing vehicular pollution that’s contributing the most to the capital’s dirty air, experts say.
“Indian cities are witnessing a rapid increase in air pollution and untamed motorization. Cities need to curb pollution from all sources, but vehicles need special attention as they emit toxic fumes within our breathing zone,” said Anumita Roychowdhury, head of the Centre for Science and Environment’s clean air programme. “India needs urgent action to leapfrog vehicle technology and fuel quality, scale up public transport, reduce dependence on cars, and promote walking and cycling.”
The study of 1,600 cities in 91 countries by WHO, released on Wednesday, said that only 12% of the people living in those cities have air quality that complies with the organization’s guidelines.
According to WHO, outdoor air pollution in both cities and rural areas was estimated to cause 3.7 million premature deaths worldwide in 2012, primarily driven by exposure to small particulate matter of 10 microns or less in diameter (PM10), which cause cardiovascular and respiratory disease and cancer.