Major League Baseball postponed two games on Wednesday because of the extremely "hazardous" air quality in the eastern United States, due to over 400 active wildfires in Canada, including more than 150 in Quebec.
For the past two days, New York City has experienced some of the worst air quality of any major city on Earth. The White Sox/Yankees game in the Bronx and the Phillies/Tigers game in Philadelphia were postponed, as was a WNBA game in Brooklyn.
According to the Environmental Protection Agency's Air Quality Index (AQI), anything over 50 is potentially harmful. From 101 to 150 is classified as "unhealthy for sensitive groups", from 151 to 200 is "unhealthy", 201 to 300 is "very unhealthy", and over 301 is "hazardous".