Wildfires Push Toronto Past Delhi for Air Pollution

Air quality in Toronto reached the worst level among major cities worldwide on Wednesday as thick smoke from wildfires in northwestern Ontario blanketed the city, bringing high temperatures and health warnings for residents.

Environment Canada recorded an Air Quality Health Index (AQHI) of 10+ in the city, representing a “very high risk”. According to Swiss technology company IQAir, Toronto ranked above some of the world's most polluted cities, including Kinshasa and Delhi. The hazardous conditions are expected to persist until at least Thursday night.

Smoke from the Canadian wildfires is also affecting parts of the US, with infants and the elderly among those most at risk. In Ontario, Canadian National Railway temporarily suspended rail operations near Armstrong as a precaution because of wildfire activity. Rail employees in the area and local residents were evacuated on Monday night.

Although this year's wildfire season started more slowly than the record-breaking seasons of 2023 and 2025, authorities are monitoring 835 active fires, 112 of which remain out of control. The provinces of Manitoba, Saskatchewan and Ontario have been hit hardest.

Experts say Toronto is experiencing an unprecedented combination of wildfire smoke and extreme heat. Temperatures are reaching about 33C, but high humidity is making it feel as hot as 39C.

(Reuters, Max)