The study, which analysed health and risk factors such as air quality that impacted 188 countries between 1990 and 2013, found that more than 5.5 million people die prematurely each year due to air pollution, with over half of those deaths occurring in China and India.
“Air pollution is the fourth-highest risk factor for death globally and by far the leading environmental risk factor for disease,” said Michael Brauer, a researcher from the University of British Columbia, "only high blood pressure, poor diet and smoking pose a higher risk to health."
Medical experts say air pollution contributes to heart disease, stroke, lung cancer, bronchitis, emphysema and acute infections.
In China, the main contributor to air pollution is particle emissions from coal burning, this source alone is responsible for more than 360,000 deaths every year according to the research.
In India, the practice of burning wood, dung, crop residues and other materials for cooking and heating was found as the main contributor to air pollution. Millions of families, among the poorest in India, are regularly exposed to high levels of particulate matter in their own homes.
“India needs a three-pronged mitigation approach to address industrial coal burning, open burning for agriculture, and household air pollution sources,” said Chandra Venkataraman, professor of Chemical Engineering at the Indian Institute of Technology Bombay, in Mumbai, India.
Brauer stated “More than 85 per cent of the world’s population live in areas that exceed the World Health Organisation’s ‘safe level’ of air pollution”.
According to the World Health Organisation (WHO) air quality guidelines, pollution should be restricted to a daily particulate matter of 25 micrograms per cubic metre.
Beijing and New Delhi typically see daily levels at or above 300 micrograms per cubic metre — or 1,200 per cent higher than WHO guidelines, researchers said.