BEIJING – From taxi tailpipes in Paris to dung-fired stoves in New Delhi, air pollution killed 7 million people around the world in 2012, according to figures released 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.

Exposure to smoke from cooking fires means that poor women are especially at risk, the agency said

Indoor air pollutants loomed as the largest threat, involved in 4.3 million deaths in 2012, while toxic air outdoors figured in 3.7 million deaths, the agency said. Many deaths were attributed to both.

Breakneck urbanization in the developing nations of Asia, especially China, is a major force contributing to the air pollution problem.

The World Health Organization report, released in Geneva, coincided with the publication of a World Bank study in Beijing about China’s drive to urbanize. The study, issued with the Development Research Center of China’s State Council, argued that many of the country’s cities had been allowed to sprawl wastefully and called for better-planned, denser cities instead.

Based on current trends, the study said, Chinese cities in the next decade will gobble up land equal in area to the Netherlands, leading to longer commutes, higher energy consumption and continued high levels of air pollution.

Dora said he hoped the stark mortality figures released would prompt people and governments alike to confront the scourge of filthy air with greater urgency.

“What’s needed is collective action,” he said. “The air you are polluting is the same air you breathe.”