Smoke from 120 out-of-control Canadian wildfires has drifted across the border, creating some of the most polluted air on the planet in parts of the United States.
The haze has reached cities ranging from Chicago to Washington, DC. Residents are experiencing reduced air quality amid the summer season.
The wildfires are burning hundreds of miles away in Canada. This marks a shift in seasonal patterns linked to global warming.
Officials have noted the smoke as a growing concern for public health in affected regions.