New York City is under an air quality advisory Wednesday as a thick plume of Canadian wildfire smoke descends into the region, bringing hazy skies, reduced visibility and unhealthy air for sensitive groups.

“Smoke from Canadian wildfires is expected to push AQI to Unhealthy for Sensitive Groups levels in NYC today,” NYC Emergency Management said. The city expects the Air Quality Index to reach between 101 and 150.

Satellite imagery Wednesday morning showed a dense band of smoke sinking south from New England toward the New York metropolitan area. Near-surface smoke is expected to increase during the afternoon and evening, with another plume moving across the region Thursday.

“Smoke and haze from Canadian wildfires are creating unhealthy air conditions across New York today,” Governor Kathy Hochul said, urging residents, particularly those with health conditions, to remain alert to air quality conditions.

The smoke is arriving during another day of dangerous heat, with temperatures approaching 100 degrees in parts of the region and heat-index values reaching as high as 106. Scattered thunderstorms are also possible later Wednesday.

Mayor Zohran Mamdani told New Yorkers, “If wildfire smoke rolls in, know your risk and head to a cool indoor space with AC if you’re sensitive to air quality.”

NYC Emergency Management advised sensitive groups to reduce strenuous outdoor activity, remain indoors where possible and keep windows closed. The agency also recommended using recirculated air conditioning and wearing a well-fitting N95 or KN95 mask when extended time outdoors cannot be avoided.

The city experienced far more severe conditions in June 2023, when Canadian wildfire smoke turned the sky orange and pushed air quality into the hazardous range.