Sticking to the Paris Agreement could save millions of lives in metropolitan areas

The data showed that over the course of this century, roughly that many people are expected to succumb to diseases relating to poor air quality in those areas.

Kolkata in India stands to benefit most from cutting carbon pollution with 4.4 million fewer early deaths by 2100.

The study, which was published in the journal Nature Climate Change, showed 11 of the 15 cities are on the Indian subcontinent.

Although localised air pollution is the largest major health hazard, 13 cities across the world are still expected to see a 2°C increase in temperature over the next decade, according to a recent report. 

The findings come as nearly 200 countries are looking at ways to uphold pledges they made as part of the 2015 Paris accord to slash emissions of planet-warming gases.

India’s capital, Delhi, and its northeastern city of Patna, along with Bangladesh’s capital, Dhaka, and Pakistan’s Lahore could each avoid between 2.6 and 4 million deaths, according to computer models applied to 154 large cities.

“They have very weak air-quality regulations currently,” said the study’s lead author professor Drew Shindell.

Ibadan in Nigeria, Bandung and Jakarta in Indonesia, and Dongguan in China are the only four megacities located in other regions of the world that could also see more than a million people’s lives saved with less air pollution, the study said.

To arrive at their conclusions, the scientists considered deaths indirectly tied to carbon dioxide, namely those due to surface-level micro-particles and ozone gas that form with high concentrations of carbon, Shindell said by phone.

Those deaths are typically caused by respiratory ailments and cardiovascular diseases such as strokes and lung cancer, the researchers said.

“Our cars still give out that pollution that leads to particles and ozone, our power plants do, our furnaces,” Shindell told Reuters.

“You see that black smoke when people fire up their oil burners in the winter - it’s black because there are particles.”

The scientists’ estimates are based on nations achieving the carbon emissions cuts necessary to meet the Paris accord’s most ambitious target of keeping the global temperature hike to 1.5°C above pre-industrial times.