Smoke from Canadian wildfires is affecting air quality and visibility across 11 US states, impacting an estimated 60 million people.
The Air Quality Index in parts of these regions is in the 'unhealthy' range, with potential for continued poor air quality into the upcoming week.
The smoke is the result of nearly 400 fires in British Columbia, sparked by 51,000 lightning strikes amid severe drought conditions.
This is Canada's worst fire season on record, with more than three times the usual area for this time of year burned in British Columbia alone.