Air quality alerts are in effect on Tuesday in 10 states as toxic smoke from hundreds of wildfires burning in Canada continues to waft into the United States, creating hazy, gray skies over major metropolitan areas, including New York City.

Canadian wildfires are the cause of an air quality alert that’s in effect for the tri-state area, according to health officials. New York City’s air quality index is at 118 on Tuesday, AirNow’s tracker indicates.

Hazy skies descend over the New York City area again on Tuesday, re-upping some air quality alerts related to Canadian wildfire smoke. As of 9 a.m., the air quality index was 118, which is considered unhealthy for sensitive groups.