Air pollution deaths: Globally Delhi 2nd and Kolkata 5th in overall number, Mumbai country topper in decadal rise; says global report

A new global report has ranked Delhi as one of the global toppers within most populous cities when gross mortality caused by toxic PM 2.5 pollutants is considered; but Mumbai leads the metro cities in India when the rise of PM 2.5 linked deaths is assessed over the last decade.

PM 2.5 is the ultrafine particulate that can invade the interior of the lungs, often taking other toxic chemicals alongside it, and can trigger a wide range of diseases and directly and indirectly can cause a huge number of deaths.

In decadal gross mortality number, Jakarta leads the pack with around 3 lakh PM 2.5 attributed deaths, but next four spots are occupied by Indian and Chinese cities; Delhi in second position while Shanghai and Beijing occupying third and fourth position followed by Kolkata in fifth position.

The findings have been derived from a recently released global study report prepared by the US based Health Effects Institute called Air Quality and Health in Cities.

According to the report, the rise of PM 2.5 linked mortality in Mumbai was about 46 percent – 10990 estimated deaths in 2010 to 16020 in 2019- during the decade of 2010- 19; just behind Dhaka that topped the South Asian populous cities with 56 percent mortality rise during the same period; 14190 in 2010 to 22090 in 2019.

Delhi, despite having second highest PM 2.5 linked gross decadal mortality globally among most populous cities with estimated 264930 deaths; falls behind Mumbai when the decadal rise of PM 2.5 linked mortality is considered which stands at 39 percent in Delhi.

Kolkata, which was found to have second highest exposure level to PM 2.5 after Delhi, has fared much better when the mortality is considered. While Kolkata has just over 2 lakh PM 2.5 linked deaths during 2010-19; the rise through the decade has been 23 percent.

The other metros in the country – Bengaluru, Chennai and Hyderabad – were found to have much less gross mortality compared to Delhi, Kolkata and also Mumbai.

“It’s a fact that south Asian cities stand extremely vulnerable to PM 2.5 pollution exposure and related mortality. A multisectoral strategy is required to counter the trend” said Pallavi Pant, a senior scientist in HEI, to The Plurals. Pant was associated with the study.

“Mumbai coming up in the pollution mortality ladder may seem to be surprising but the long-time pollution figures also vindicate the trend. The HEI report shows that Mumbai’s annual PM 2.5 exposure level has increased consistently over last decade, and record one of the highest rises in India; 24 percent” explains an environmentalist.

“Deaths from six diseases were included to estimate the burden on health associated with PM2.5: ischemic heart disease, stroke, lower respiratory infections, lung cancer, type 2 diabetes, and chronic obstructive pulmonary disease (COPD)” explains the report.

“How can they directly link all the deaths under these categories with PM 2.5 exposure” asked a senior official from West Bengal Pollution Control Board, which has questioned the veracity of both PM 2.5 pollution exposure level as well as related mortality data released for Kolkata.

“The mortality figure of Kolkata seems to be overestimated” also observed a senior scientist working with air pollution.

“It was completely science driven and we have reached the mortality numbers under various categories based on established attribution values; and that applies for all the cities including Kolkata” explained Pant.