NEW YORK — Hazy skies and low air quality returned to the five boroughs on Monday, as smoke from Canadian wildfires again created a gray scene in the New York skies. All of New York state and almost all of New England was under an air quality alert from the National Weather Service on Monday afternoon.

Air-quality alerts have been posted in New York City, with 740 fires raging across Canada from the Arctic Circle to southern Ontario.

An air quality advisory is in effect for New York City on Monday due to wildfire smoke from Canada, according to officials. Other areas that are affected by the advisory include the Hudson Valley, Adirondacks,