Smoky conditions from Canada wildfires in Chicago

Smoke from Canada's worst-ever wildfires is severely impacting air quality across Ontario and at least 15 US states, with monitors warning that over one hundred million people face potentially unhealthy conditions.

Chicago, Detroit and Cleveland recorded some of the worst air quality in the United States, with residents told to stay inside or limit outdoor activity as smoke blanketed huge swaths of the country just weeks after communities suffered similar disruptions from Canada's hundreds of active forest fires.

Alerts were issued from Ontario to northern US states Minnesota and Michigan, across to New York and down to the southeastern states of North Carolina and Georgia, the latest dangerous air conditions in much of North America's Great Lakes and Mid-Atlantic regions.