Chicago's air quality has become hazardous due to Canadian wildfire smoke. This pollution has affected over 125 million people across the Midwest and Northeast. Health officials advise residents to stay indoors and minimize outdoor exposure. The smoke is expected to persist through Friday before gradually improving. Authorities recommend monitoring air quality updates until conditions normalize.

Wildfires in Canada are pouring thick clouds of smoke into the US and will usher in unhealthy air quality for millions of people in Northeast and Midwest.

States warned residents about air quality issues that could last for days