Smoke from the blazing Minnesota fires in Minnesota drifted into Ontario on that day . Environment Canada listed areas in Ontario among the worst globally for air quality in recent reports . The region’s urban centers faced urgent warnings about hazardous air from the drifting haze. Prolonged dryness and strong winds helped fires spread at breakneck speed through Minnesota and nearby states. Toxic smoke drifted north, blanketing Canada in a heavy curtain of contaminants.