The concentration of respirable pollutants in Mumbai’s air is six times the international safe limits, according to a World Health Organisation (WHO) report on pollution in 3,000 cities in 103 countries. Mumbai was the 39th-most polluted on the list of 122 Indian cities.
WHO compared levels of PM10 (particulate matter), smaller than 10 microns, and PM2.5, smaller than 2.5 microns, between 2008-2013. PM includes floating particles of sulphate, nitrates and black carbon that can penetrate deep into the
lungs and the cardiovascular system, posing a risk to human health.
Mumbai is the 147th most polluted city internationally for PM2.5 and 128th for PM10. Gwalior and Allahabad are the second- and third-most polluted cities in the world, while Patna and Raipur are among the top 10 polluted cities in the world; Delhi is ranked 11th.
WHO looked at data provided by the Central Pollution Control Board (CPCB) from the Sion and Bandra pollution monitoring stations.
The annual average for PM10 in Mumbai was 117 microgrammes per cubic metre (µg/m3) against the safety limit of 20µg/m3 [WHO safety limit]. Concentration of PM2.5 was 63µg/m3 against a safety limit of 10µg/m3 [WHO safety limit]. Mumbai recorded a rise in PM2.5 levels since the last WHO report in 2014 when levels of PM2.5 was 45µg/m3, though PM10 concentration has improved from 136µg/m3 in 2014.
“Urban air pollution continues to rise at an alarming rate, wreaking havoc on human health,” said Dr Maria Neira, WHO director, department of public health, environmental and social determinants of health.
“At the same time, awareness is rising and more cities are monitoring their air quality. When air quality improves, global respiratory and cardiovascular-related illnesses decrease,” Neira said.
The WHO report indicated that Navi Mumbai recorded higher pollution levels as compared to Mumbai and Thane. PM10 and PM2.5 levels at Navi Mumbai, which ranked 36th in the national list, were 120µg/m3 and 64µg/m3 respectively, while Thane, which ranked 86th for PM10 (73µg/m3) and 87th for PM 2.5(39µg/m3). Tejpur in Assam had the cleanest air in India with PM10 and PM2.5 levels at 11µg/m3 and 6µg/m3, respectively.