Minneapolis recorded the worst air quality of any major city in the world on Thursday as dense smoke from wildfires burning across northern Minnesota and Ontario, Canada, covered the region.
Air quality conditions deteriorated rapidly Wednesday evening, with much of the city reaching the “hazardous” category and remaining there through Thursday. In some locations, the Air Quality Index (AQI) climbed to 460—well above the hazardous threshold of 300.
Detroit also ranked among the cities with the poorest air quality globally as wildfire smoke spread across the Upper Midwest.
Health officials urged everyone to stay indoors while the hazardous conditions persist, warning that the smoke poses serious health risks to people of all ages.
The smoke is being fueled by numerous wildfires across Canada, where it has drifted south into parts of the northeastern and upper Midwestern United States. Ontario’s Ministry of Natural Resources reported that more than 183 wildfires were active on Wednesday.
Officials said the fires in northern Minnesota have spread quickly due to a combination of extreme heat, dry vegetation, strong winds, and an increase in lightning strikes. Recent temperatures in the region have soared into the 100s, far above the typical upper-70s temperatures expected this time of year.
