Canada's Wildfires Give Detroit, Minneapolis, and Toronto the World's Worst Air

More than 800 wildfires are burning across Canada, and most are not under control. Smoke from Ontario's fires has made the air unhealthy in Thunder Bay and Toronto. A tracking group called IQAir ranked Detroit, Minneapolis, and Toronto as having the worst air quality in the world. Winds from the northwest are expected to blow smoke into northern US states through the weekend.