Smoke from the explosive forest fires in northern Minnesota drifted into southern Ontario on the current stretch of days. Environment Canada listed areas in Ontario among the worst globally for air quality in recent reports . Toronto faced urgent warnings about hazardous air from the distant fires . Prolonged dryness and strong winds helped wildfires spread at breakneck speed through Minnesota and nearby states. Toxic smoke drifted north, blanketing Canada in a thick veil of contaminants.