Air pollution could be directly responsible for the deaths of more than two million people every year, a new study shows.
Most of the deaths -- 2.1 million -- are caused by fine particulate matter lodging deep in the lungs, which could cause cancer and other respiratory diseases.
An additional 470,000 are killed annually as a result of human-caused increases in ozone pollution.
Researchers ranked areas around the world by the number of premature deaths due to air pollution. The list includes:
1. East Asia - More than 1 million people die prematurely every year from fine particulates and 203,000 die from ozone pollution.
2. India - An estimated 397,000 die from fine particulates and 118,000 die from ozone pollution.
3. Southeast Asia - An estimated average of 158,000 die from fine particulates and 33,000 die from ozone pollution.
4. Europe - Around 158,000 people die from fine particulates annually and 32,800 die from ozone pollution.
5. North America - An average of 43,000 die from fine particulates and 34,400 die from ozone pollution.
The study was published online by the Journal of Environmental Research Letters.