Wildfire smoke from northern Ontario and the Prairies caused poor air quality and restricted visibility in Toronto, Ottawa, and Montreal on Friday. Environment Canada issued specific air quality warnings, advising individuals who are vulnerable to avoid outdoor activities and seek medical attention if symptoms develop, according to Associated Press.

Meteorologist David Phillips told that wildfire activity is increasing nationwide, significantly impacting air quality. “Only a few see the flames, but millions smell the smoke,” he noted.

According to IQAir, Toronto recorded the second-worst air quality in the world Friday afternoon,  Associated Press reported.