Toronto records world's worst air quality as wildfire smoke blankets city

Toronto recorded the worst air quality among major cities worldwide on Wednesday, according to Swiss air quality monitoring firm IQAir, as Canadian authorities urged residents to remain indoors amid worsening wildfire smoke.

The city ranked ahead of New Delhi and Kinshasa, the capital of the Democratic Republic of Congo, after smoke from wildfires turned Toronto's skies a hazy yellowish-grey.

"The biggest contributor to Toronto's spike in air pollution right now is wildfires, though the higher than average temperatures are also playing a role," Armen Araradian of IQAir told AFP.

Although Canada's 2026 wildfire season has been less severe than recent years, more than 800 wildfires remain active across the country. Smoke from fires burning in northwestern Ontario drifted south, significantly affecting air quality in Toronto.

More from World

In response, city officials shut public pools, cancelled summer camp programs and closed the official FIFA Fan Festival ahead of Wednesday's FIFA World Cup semi-final between England and Argentina.

Montreal also experienced deteriorating air quality on Tuesday, though conditions were less severe than in Toronto.

The smoke spread beyond Canada, reducing air quality across parts of the northeastern United States. Pennsylvania, New York, Connecticut, Massachusetts, Maine and New Hampshire were among the states affected.

New York state authorities warned residents that they "may see visible smoke and hazy skies across the state and spikes in smoke-related pollution."

The poor air quality comes as Canada continues to grapple with a record-breaking North American heat wave. Extreme heat and humidity stretching from the Mountain West have extended into Ontario and the densely populated eastern United States.

While temperatures in Ontario are expected to ease by the weekend, officials have warned that the wildfire threat is likely to persist throughout the remainder of the summer.

Canadian wildfires have burned around 1.9 million hectares so far this year—an area nearly the size of Slovenia. Although significant, the total remains well below 2023, Canada's worst wildfire season on record, when nearly 18 million hectares were scorched.