Smoke in much of Alberta and western Saskatchewan is causing very poor air quality, while wildfires continue to rage in Canada's north.
Environment Canada has issued air quality warnings for regions of both Prairie provinces, saying smoke is also reducing visibility in some areas.
The weather office says those most at risk, including adults aged 65 and up, babies and people with pre-existing health conditions, should avoid strenuous activities.
They should also seek medical help if they experience anything like eye, throat and nose irritation, coughing or chest pains.
The warning comes as wildfires in the Northwest Territories, including one not far from the hamlet of Fort Providence, forced hundreds to flee their homes.
The fire southwest of Yellowknife has so far scorched 1,020 square kilometres of land.
RCMP say officers are conducting patrols in Fort Providence, but calls for service from those who remain in the community are hindering firefighting efforts.
This report by The Canadian Press was first published Sept. 2, 2025.
The Canadian Press
