Smoke from the wildfires in Canada has descended on the Great Lakes region and the Midwest, with the cities of Chicago and Detroit having the worst air quality in the world, the report said.
The affected areas in the northern parts of the United States could continue to have poor air quality for the next few days thanks to a low-pressure system, according to the National Weather Service.
About 92 million people in the United States are under air quality alerts and the National Weather Service also issued air alerts for northeastern Illinois, northwestern Indiana and southeast Michigan.