Canada wildfires: Smoke choking major US cities July 17, 2026Smoke from hundreds of wildfires burning in Canada has prompted air quality warnings across parts of the United States on Friday, triggering fresh tariff threats from US President Donald Trump. More than 800 wildfires are burning across Canada and the clouds of dense smoke have spread south, choking major cities including Detroit, Chicago, and New York. Cities record 'hazardous' air quality readings Both Detroit and Chicago issued air quality index readings in the "hazardous" range, while in New York, the metro area was shrouded in a smoke tinted haze, deemed unhealthy for sensitive groups. National Weather Service (NWS) forecasts have warned that conditions may worsen overnight into Saturday morning. The AFP news agency cited NWS meteorologist Peter Mullinax as saying that wind over the Great Lakes region could cause more smoke to pour into the Northeast, which could keep skies hazy. There is concern from some air quality forecasters that more smoke is blown south after weekend weather systems. Trump threatens Canada with more tariffs over wildfires US President Trump said he was "holding Canada responsible" for the wildfires, threatening higher tariffs on the neighboring country to make up for the "cost of this pollution." "We are holding Canada responsible for the fact that they are not properly maintaining their Forests, and Brush therein, and the United States is being unnecessarily invaded by filthy, polluted, and unhealthy air, the quality of which is dangerous, and totally unacceptable!" Trump wrote on his Truth Social platform. He added that he will reach out to Canada's prime minister to "find out what they are going to do about it." World Cup organizers 'monitoring closely' FIFA World Cup Organizers said they were "monitoring closely" the situation with the final between Spain and Argentina due to