美国有线新闻 CNN 世卫组织发布最新报告 全球每年700万人死于空气污染（在线收听）

There's a good chance that the air you breathe is too polluted to be healthy.

That's ac???cording to a new study just released this week by the World Health Organization, which is part of the United Nations. It says the vast majority of the global population is breathing air that has high levels of pollutants. Asia and Africa are the worst continents for this.

But in cities across North and South America, Europe and the eastern Mediterranean, pollution levels are still too high to be what the WHO calls healthy.

The cities in America with the most polluted air included Los Angeles, California, as well as Bakersfield, Fresno and Napa. They also included Indianapolis, Indiana, Louisville, Kentucky, and St. Louis, Missouri. But none of these places have anywhere near the level of pollution that's seen in Peshawar, Pakistan, Cairo, Egypt, and Al Jubail, Saudi Arabia.

The report says pollution isn't just a city air problem. It's bad in people's homes and poor areas of the world, where wood and charcoal power stoves and open fires are used to cook and heat. The upside of the study is that many cities are keeping track of pollution and that can lead to steps to clean it up.

LYNDA KINKADE, CNN CORRESPONDENT: Seven million people die each year from a manmade cause, air pollution. That's according to a new study by the World Health Organization.

They also found that nine out of every 10 people on the planet breathes air that contains high level of pollutants.

The WHO says it's the world's most comprehensive database on pollution. The organization collected data from more than 4,300 cities and 108 countries. Although air pollution affects people worldwide, low and middle income countries experience far worse.

Many of the top cities on the list are in India. While attention is usually paid to Delhi and Mumbai, the WHO founded the cities Kanpur, Faridabad, and Varanasi are the top of the list.

Environmentalists warn that India is sitting on a toxic time bomb. The U.S. based Health Effects Institute found that over 1 million people die every year in India alone from the impacts of air pollution.

This pollution is created mostly by car and truck emissions, manufacturing, power plants and farming. The particles in the air are a mix of solid and liquid droplets that get embedded into the lungs when we breathe. It leads to multiple health conditions including asthma, lung cancer and heart disease.

Lynda Kinkade, CNN.