Smoke from hundreds of Canadian wildfires blanketed the eastern United States this weekend, choking cities from the Midwest to the Mid-Atlantic with hazardous air and casting a pall over preparations for Sunday's FIFA World Cup final between Argentina and Spain at the open-air New York/New Jersey Stadium in East Rutherford, New Jersey. At one point on Saturday, New York City ranked as the most polluted city in the world according to air quality tracker IQAir, with Toronto and Washington, D.C., close behind. Landmarks including the Washington Monument and the Lincoln Memorial were swallowed by an orange-tinged haze, a baseball game in Cleveland was postponed, and residents across multiple states were urged to stay indoors.

The scale of the fires driving the crisis is immense. More than 950 wildfires were burning across Canada as of Saturday morning, according to the Canadian Wildland Fire Information System. In Ontario alone, nearly 200 wildfires have already scorched more land than all of last year's fires combined, forcing at least ten northern communities to evacuate. In British Columbia, around 100 fires broke out following some 4,000 lightning strikes on Friday. Fire Chief Dave Tarini of Thunder Bay, Ontario, described the season as unprecedented in more than 35 years of firefighting. Fires were also burning in the Boundary Waters Canoe Area Wilderness in Minnesota. Climate scientists and officials attribute the intensifying fire seasons to climate change.

The smoke prompted a sharp political dispute between Washington and Ottawa. President Donald Trump posted on social media that the United States was being