About 7 million deaths were attributable to air pollution in 2012, according to new estimates released by the World Health Organization. This more than doubles the figure from 2011.

The WHO estimates that approximately 3.7 million premature deaths are attributable to outdoor air pollution, and another 4.3 million are atrributable to indoor air pollution. Both kinds of pollution tend to affect more people in poor and developing countries, especially in Asia. While outdoor air pollution tends to be an urban phenomenon, indoor air pollution affects more women and children in rural areas, where women are forced to cook with solid fuels like coal, dung and agricultural byproducts.

In total, most deaths-by-atmosphere in 2012 were the results of stroke: 2,296,900. A close second was coronary artery disease, followed by chronic obstructive pulmonary disease, lung cancer and acute lower respiratory infections. Nine percent of those killed were children, while the rest was about split even between men and women.

"Few risks have a greater impact on global health today than air pollution; the evidence signals the need for concerted action to clean up the air we all breathe," said Dr. Maria Neira in a WHO press release.

By far the regions most at risk were located in South East Asia and the Western Pacific, which is perpetually blanketed by a haze of filth (the Southeast Haze) due to pollution from massive land-clearing fires mostly initiated by big palm oil companies.

The WHO says the figures are their most accurate yet due to advancements in atmospheric measurement technology. Distressingly, the number of deaths attributable to air pollution in 2012, doubled the estimate in 2011. Representatives from the organization said major policy changes are needed to counter the problem.

"Excessive air pollution is often a by-product of unsustainable policies in sectors such as transport, energy, waste management and industry. In most cases, healthier strategies will also be more economical in the long term due to health-care cost savings as well as climate gains,” said Dr. Carlos Dora, WHO Coordinator for Public Health, Environmental and Social Determinants of Health, in a press release.