The most polluted air in the world today is in three major US cities – where readings are multiple times worse than the notoriously noxious Delhi, India – due to raging wildfires in Canada.
Air pollution in Detroit, Michigan, was the worst in the world Thursday, with a score of 724 on the live global air quality index (AQI), according to IQAir – which shows that the atmosphere becomes “hazardous” starting at 301.
Toronto, Canada, saw the second-highest pollution levels, with a score of 271 – which falls within the “very unhealthy” category between 201 and 300.
Smoke will raise significant air quality concerns today for an area spanning from the Upper Midwest into the Ohio Valley, Northeast, and Mid-Atlantic. Code orange and higher alerts are currently in effect for practically all affected areas.
Smoke will continue to slowly traverse… pic.twitter.com/7QKX2RzTgI
— Max Velocity (@MaxVelocityWX) July 16, 2026
The third- and fourth-most polluted air was found in Minneapolis, Minnesota, and Chicago, Illinois, where the scores were 257 and 250, respectively.
Delhi – which traditionally tops annual pollution reports – had a score of 150, within the “unhealthy for sensitive groups” range, on Thursday, according to the list.
More than 100 wildfires are still burning in Canada and northern Minnesota, with parts of the Midwest having experienced hazardous air quality, according to USA Today.
