"Each year, more people die from air pollution-related disease than from road traffic injuries or malaria", it said.
Ten countries with the highest mortality burden attributable to air pollution in 2017 were China (1.2 million), India (1.2 million), Pakistan (128,000), Indonesia (124,000), Bangladesh (123,000), Nigeria (114,000), the United States (108,000), Russian Federation (99,000), Brazil (66,000), and the Philippines (64,000), the report states.
The report was co-produced by the Institute for Health Metrics and Evaluation at the University of Washington.
The State of Global Air 2019, which used data from the period 1990 to 2017, estimated that if air pollution levels met the World Health Organisation (WHO) guidelines, life expectancy in Bangladesh would have seen the highest expected gain of almost 1.3 years.
"Air pollution exposures collectively reduce life expectancy by 20 months on average worldwide", University of Texas assistant professor Joshua Apte wrote in the report.
In 2017, 846 million people in India and 452 million people in China were exposed to household air pollution.
It trumps better-known risk factors like malnutrition, alcohol use, and physical inactivity in terms of the ill-health effects associated with it.
Its conclusions illuminate what "we're seeing more and more of each year" in terms of health impacts stemming from air pollution, said Alastair Harper, head of advocacy at Unicef UK, the British arm of the United Nations children's agency.
While it does not give an exact figure for Canada, a map shows the country had less than 10,000 deaths attributable to air pollution in 2016.
In March 2019, Greenpeace in its report on air pollution highlighted that out of 20 most polluted cities in the world, 18 are in India, Pakistan and Bangladesh, while Beijing, once among the most polluted cities in the world, ranked 122nd in the list of most polluted cities in 2018.
"In much of the world, just breathing in an average city is the health equivalent to being a heavy smoker", he added in a statement.
Air pollution is cutting Canadian life expectancy by more than three months, a new study claims.
"These and future initiatives have the potential, if fully implemented as part of a sustained commitment to air quality, to result in significant health benefits", he said.
Frank Kelly, a professor of environmental health at King's College in London, said that until recently little data had been available on air pollution challenges in sub-Saharan Africa.
Worldwide, air pollution reduced life expectancy by an average 20 months in 2017, a global impact rivalling that of smoking; this means a child born today will die 20 months sooner, on average, than would be expected without air pollution.
O'Keefe also pointed to China's levels of air pollution, which have bucked the developing world trend by starting to fall in the last several years. India has initiated major steps to address pollution sources like the Pradhan Mantri Ujjwala Yojana, accelerated Bharat Stage VI clean vehicle standards and the new National Clean Air Programme, the report said.