A study by the World Health Organization and Columbia University found that the United States is the nation’s most polluted region, followed by India, Russia, China, the Philippines, Vietnam and Bangladesh.

The study also showed that the most dangerous places in the U.S. are in the South, West and East, as well as in the Midwest and Northeast.

The report said the region’s highest levels of pollution were found in the Pacific Northwest and the Gulf Coast.

A recent study also found that pollution in the United Kingdom was the worst in Europe and the most harmful in the Asia-Pacific region.

The U.K. is the third most polluted country in the OECD, according to the report, and its most polluted city is in London.