Smoke from more than 800 blazes has affected cities from Toronto to New York, as well as the US Midwest.

More than 800 wildfires are burning across Canada, with air quality alerts now extending south into multiple US states. The air quality in large parts of the northern states of Michigan and Minnesota is deemed "hazardous" by the US Air Quality Index program, with people recommended to stay indoors. Alerts span the Upper Midwest, the Great Lakes region and into the northeast, the US national weather service (NOAA) said in an update on Thursday. In Canada, one fire in northern Ontario forced residents from local First Nations to evacuate, with one chief saying that her community has been "burnt to ashes". There are currently 858 fires actively burning in Canada, including 30 new fires on Thursday, according to the Canadian Wildland Fire Information System. The vast majority are burning out of control. The large cluster of fires affecting northwestern areas of Ontario are responsible for sending thick plumes of smoke and poor air quality across Thunder Bay and Toronto, with lower concentrations of smoke high in the atmosphere drifting over the Great Lakes and above New York with hazy skies and redder sunrise and sunsets likely. In western regions of New York state, the air quality on Thursday is considered "very unhealthy", while in the New York City metro area the air quality is "unhealthy". New York has extended its heat emergency plans and activated its air quality emergency protocols - with hundreds of cooling centers and KN95 masks being made available citywide.