Poor air kills ‘extra’ 12,000 a year in Mumbai

The study, which looked at mortality data from 2004 and 2013 across 10 cities in Maharashtra, analysed excess deaths caused by air pollution including heart and respiratory diseases

Air pollution kills 12,000 more Mumbaiites than expected every year, says an Indian Institute of Technology, Bombay (IITB) study. Excess death is the difference between actual deaths and expected deaths to a population at risk by inhaling poor quality air.

The study, which looked at mortality data from 2004 and 2013 across 10 cities in Maharashtra, analysed excess deaths caused by air pollution including heart and respiratory diseases. (File photo)

The study, which looked at mortality data from 2004 and 2013 across 10 cities in Maharashtra, analysed excess deaths caused by air pollution including heart and respiratory diseases.

Researchers said 91% to 97% excess deaths in Mumbai was a result of inhaling harmful solid and liquid particles in the air – particulate matter of less than 10 microns in diameter (PM10). PM10 is also responsible for mortality due to respiratory diseases (86.3%–95.9%) and cardiovascular diseases (76.3%–86%).

To calculate additional deaths, the IIT-B team used Risk of Mortality/Morbidity due to Air Pollution – a mathematical model – to estimate direct health impacts of the three critical air pollutants in 10 cities of Maharashtra. The team adopted the WHO guidelines for PM, nitrogen dioxide and sulphur dioxide concentrations, along with exposure-response relationship (exposure to the pollutant - morbidity and mortality) and the percentage of the incidence of a disease in both exposed and unexposed populations.

The study said Mumbai has the highest annual average excess number of total mortality at 1,192 per one million population followed by mortality due to cardiovascular diseases (724) and respiratory diseases (121). Since the city’s population is around 12 million, the excess deaths are around 12,000. “Particulate matter released due to open solid waste burning and small scale bakeries are largely responsible for pollution in Mumbai. If adequate steps are not taken, 90% air-quality related mortalities by 2030 will be related to PM10 exposure,” said Kamal Jyoti Maji, lead investigator.