Smoke from wildfires in northwestern Ontario is causing very poor air quality and reduced visibility across Canada. Environment Canada issued alerts for major cities on Wednesday.
Toronto ranked worst among major cities worldwide for air quality, scoring eight on the Air Quality Health Index. Yellowknife also reached high-risk levels with a score of seven.
The alerts warn that everyone's health is at risk. Residents are advised to limit outdoor activities and keep windows closed. Vulnerable groups, including the elderly and those with chronic conditions, should avoid strenuous outdoor activity.
Conditions are expected to persist until Friday in Ontario and Thursday in Manitoba. A similar warning was issued for Vancouver.