Before and after images as NYC and DC covered in toxic haze from Canadian wildfires

Smoke from Canadian wildfires shrouded US cities in a noxious haze again Thursday, delaying flights and disrupting outdoor events.

Thick skies and an acrid campfire smell hung over the capital Washington, with parts of the mid-Atlantic region reaching "Code Maroon," the highest category of the Air Quality Index, signaling hazardous conditions. More than 111 million people in the United States were living under air quality alerts due to the fires, the Environmental Protection Agency said Thursday. 

"Millions of Americans are experiencing the effects of smoke resulting from devastating wildfires burning in Canada, another stark reminder of the impacts of climate change," President Joe Biden said in a statement. He added he was sending extra resources to Canada, including "additional firefighters and fire suppression assets such as air tankers.