Toronto, along with much of the province and multiple states in the northeastern United States, was blanketed by thick smoke drifting from multiple wildfires in northwestern Ontario on Wednesday, leading to an orangey hue in the skies.

Environment Canada issued an orange warning for the Toronto area as air quality worsened because of the smoke, indicating significant health risks for people outdoors. The city’s air quality was also among the worst in the world for most of Wednesday, according to Swiss-based global air quality monitor IQAir.