Environment Canada is warning of poor air quality and extreme heat in Toronto on Monday as southern Ontario braces for a week filled with hot and humid weather.

There’s a layer of haze in the air, as smoke from burning wildfires has blown into southern Ontario. And according to the World Air Quality Index website, Toronto is one of the worst places in the world right now for air quality.

With various air quality indexes available, and as wildfire smoke becomes an increasing health risk, here’s what often goes into the decision to play sports or not — and how to make sense of air quality indexes when making your own decision.

The poor air quality that has blanketed swaths of central and Western Canada is not only infiltrating the lungs, but also distressing the mind.

Expect deteriorating air quality across parts of Ontario heading into the new workweek as upper-level winds blow wildfire smoke into the region. Some of the smoke could mix down to the surface, lowering air quality from northern Ontario to the Greater Toronto Area.

While some organizations have published clear air quality thresholds or contingency protocols for wildfire smoke, FIFA's plans remain unclear less than a year out from the 2026 World Cup.