Geneva - Air pollution killed an estimated 7 million people around the world in 2012, making it the biggest environmental health risk, the World Health Organisation (WHO) said Tuesday.
"The risks from air pollution are now far greater than previously thought or understood, particularly for heart disease and strokes," said WHO public health chief Maria Neira.
The situation was worst in developing and emerging countries in Southern Asia, South-East Asia and East Asia, where a total of 3.3million deaths were linked to indoor air pollution and 2.6 million to outdoor pollution, the WHO said.
Use of wood, coal or dung for cooking is the biggest indoor polluter.
In Europe's industrialised countries, 279,000 deaths could be traced to air pollution.
The WHO said bad air quality outside was a result of unsustainable policies in the transport, energy and waste sectors, as well as in industry.
Cleaning up the air would reduce risks, especially for vulnerable children and the elderly, the UN health body said.