Toronto has been ranked as having the worst air quality in the world as of July 15, 2026, due to smoke from forest fires in northwestern Ontario.According to IQAir, a Swiss air quality monitoring company, the city surpassed major cities like Kinshasa, Delhi, and Dubai.

Environment Canada issued a yellow air quality warning, advising residents to limit outdoor activities and take precautions due to potential health risks such as eye irritation, headaches, and respiratory issues.The situation is compounded by a heatwave, with temperatures reaching up to 36°C and humidex values making it feel like 42°C.

The smoke is expected to persist into Thursday, with health officials urging vulnerable populations—such as the elderly, children, and those with preexisting conditions—to avoid strenuous outdoor activities.

The article also notes the ongoing heatwave, which has already seen record temperatures, and warns of potential health impacts from both the smoke and extreme heat.