More than 6 million deaths a year are believed to be linked with air pollution
92% of the world's population live in areas where air quality levels exceed World Health Organisation (WHO) limits, a new model has shown.
The model devised by the organisation highlights "air pollution danger spots" around the world.
An interactive map shows particularly high levels of air pollution in areas such as Saudi Arabia, China, India, Bangladesh and north Africa.
According to WHO, human influences such as industry, inefficient modes of transport transport, household fuel and coal-fired power plants are among the sources of air pollution - alongside environmental factors such as dust storms.
Figures show that around 6.5 million deaths - or 11.6% of all global deaths - in 2012 were associated with either indoor or outdoor air pollution. That includes around 3 million deaths linked with ambient (or outdoor) air pollution.
Around nine out of ten air-pollution-related deaths occur in low- and middle-income countries.
Dr Flavia Bustreo, Assistant Director General at WHO, said: "Air pollution continues take a toll on the health of the most vulnerable populations – women, children and the older adults. For people to be healthy, they must breathe clean air from their first breath to their last."
Dr Maria Neira of WHO's Department of Public Health, Environmental and Social Determinants of Health added: "This new model is a big step forward towards even more confident estimates of the huge global burden of more than 6 million deaths – 1 in 9 of total global deaths – from exposure to indoor and outdoor air pollution."