Wildfires in northwestern Ontario, Canada, have triggered mass evacuations and sent hazardous smoke across parts of the US and Canada. More than 130 fires remain active, with at least 60 currently out of control.
The smoke has caused dangerously high and unhealthy air quality levels in several cities, including New York, Chicago, Detroit, Minneapolis, and Toronto. Cities across the Great Lakes states registered levels ranging from unhealthy to hazardous, leading officials to advise residents to stay inside.
On July 16, Detroit recorded the world's worst air quality with a pollutant index of 600. Air quality warnings have extended from Minnesota to New York, and the National Weather Service indicated that the smoke could linger until the end of the week.