An astonishing 5.5 million people are dying each year because of air pollution, a startling new study presented at the American Association for the Advancement of Sciences is claiming.

More than half of those deaths are happening in China and India, fast-growing economies that are dealing with ever more pervasive smog problems that the nations have struggled to get under control, according to a CBS News report.

Power plants, manufacturing facilities, vehicle exhaust, and burning wood and coal are the main causes of air pollution, which sit in the atmosphere and are breathed in by people throughout the day, This new study sheds light on just how great the health effects are of pervasive air pollution, and thus the importance of efforts to combat the problem.

The research team includes experts hailing from China, India, the United States, and Canada, and is part of the broader Global Burden of Disease Study led by the Institute for Health Metrics and Evaluation at the University of Washington.

And it’s not just a problem in China and India — 85 percent of the world’s population breathe in dangerous levels of air pollution based on World Health Organization standards.

And don’t think it’s just a problem in urban areas. Residents of rural communities in poorer countries can absorb air pollution from cooking with materials like coal and wood.

Researchers estimate that about 55 percent of the 5.5 million who die each year are in China and India, with coal burning appearing to be the main cause in China. Wood, dung, and other biomass appeared to be a major culprit in India.

It’s not all bad moves. Some areas that have been most affected by air pollution are seeing improvements thanks to policy changes. High-income nations have done well to improve their air quality, but the battle still remains to get poorer countries on track as well.