BEIJING — From taxi tailpipes in Paris to dung-fired stoves in New Delhi, air pollution claimed seven million lives around the world in 2012, according to figures released Tuesday by the World Health Organization. More than one-third of those deaths, the organization said, occurred in fast-developing nations of Asia, where rates of cardiovascular and pulmonary disease have been soaring.

Around the world, one out of every eight deaths was tied to dirty air, the agency determined — twice as many as previously estimated. Its report identified air pollution as the world’s single biggest environmental health risk.

“The big news is that we have a better understanding of how large a role air pollution plays in strokes and coronary heart attacks,” said Dr. Carlos Dora, coordinator of public health and the environment at the organization. “Given the astronomical costs, countries need to find a way to prevent these noncommunicable diseases.”

The report found that those who are most vulnerable live in a wide arc of Asia stretching from Japan and China in the northeast to India in the south.