Forest wildfires have caused air quality to deteriorate in many parts of Canada, with railway transportation being affected.

In recent days, wildfires sweeping through the northwest of Ontario, Canada have caused a sharp deterioration in air quality in many parts of the country, and have disrupted railway traffic. Due to the smoke and haze from the wildfires, on the morning of the 15th, Toronto, Canada's largest city, ranked the lowest in air quality among major cities around the world. Data released by Canada's Department of Environment showed that the air quality health index in Toronto was at a "high risk" level that day. The capital, Ottawa, also issued an air quality warning due to the thick smoke from the wildfires and the hot and humid weather, high humidity causing smoke particles to linger in the air, turning the sky yellow.