Toronto's air quality plummeted to the worst of any major city worldwide on Wednesday, as thick smoke from over 100 active wildfires in northwestern Ontario blanketed Canada's largest metropolis.

Monitoring service IQAir reported that the city surpassed New Delhi and Kinshasa for the poorest air quality, prompting immediate health concerns across the region.

Orange Haze Descends on City

A dense, orange haze settled over Toronto throughout Wednesday, transforming the city's skyline into a hazy yellow. Residents woke to a pervasive smell of smoke and significantly reduced visibility, impacting daily life.

Environment Canada issued urgent health warnings, advising residents to limit outdoor activities and protect vulnerable populations from the dangerous airborne particulates.

toronto skyline wildfire smoke orange haze

The smoke plumes originated from more than 100 active wildfires burning across northwestern Ontario, a common occurrence during Canada's hot, dry summer months. Prevailing winds carried the smoke hundreds of kilometres southeast, directly over densely populated areas.

Smoke Extends to US Northeast

The far-reaching effects of the Canadian wildfires extended well beyond the national border, impacting air quality across the northeastern United States. Cities such as Detroit and Minneapolis also reported significantly degraded air conditions, ranking among the worst in major U.S. urban centres.

Wildfire smoke contains fine particulate matter that can irritate the respiratory system, exacerbate existing conditions like asthma and heart disease, and pose risks to overall public health. Officials continue to monitor the situation, with forecasts suggesting the smoke may persist in varying densities over the coming days, depending on wind patterns.