Canada says it has identified India’s top diplomat in the country as a person of interest in the assassination of a Sikh activist there and expelled him and five other diplomats

One of the unions issued a strike notice just hours after the freight trains resumed operations following a brief lockout. A work stoppage could disrupt supply chains.

Two major Canadian freight rail companies locked out thousands of workers on Thursday, shutting down cross-border shipping routes.

About 25,000 people were ordered to evacuate Jasper and Jasper National Park, leading to crowded highways as they tried to escape fires that have scorched more than 17,000 acres.

Nicco's mom Terri Lawson said her son "takes his routes seriously."

With wildfires burning across Canada, meteorologists said conditions are stacking up for a replay of last year's fire season when skies over New York City turned orange.

As the threat of an active wildfire season looms, there are steps individuals can take to mitigate the effects of wildfire smoke in their homes.

Dozens of wildfires burning in Alberta and British Columbia are impacting air quality in North Dakota, Minnesota and other U.S. states.

A motive is unknown at this time, police said.

ABC News' Phil Lipof speaks with Sandy LeClerc, the partner of World Central Kitchen aid worker Jacob Flickinger, who was killed in an Israeli airstrike, about the impact on her family.

Former Canadian Prime Minister Brian Mulroney dies at 84, his daughter announced.

Delta flight 135 from Amsterdam to Detroit diverted to Goose Bay Airport in the Canadian province of Newfoundland and Labrador around 3:15 p.m. on Sunday, Dec. 10.

The car crashed and exploded on Rainbow Bridge near Niagara Falls.

It not immediately clear what caused the vehicle explosion.

All four Canada-U.S. bridges over the Niagara River have been closed out of an abundance of caution while the investigation continues.

Videos of the aftermath appear to show a plume of smoke at the checkpoint.

A Jewish school in Montreal was shot at early Sunday, the second time in under a week the school has been targeted with gunfire, officials said.

The New York skyline was shrouded in a light haze after smoke from the Canadian wildfires returned to U.S. skies.

During Ukrainian President Volodymyr Zelenskyy's visit to the Canadian parliament on Friday, speaker Anthony Rota called 98-year-old veteran Yaroslav Hunka a "hero."

Hardeep Singh Nijjar was gunned down in June outside a temple in Surrey.

Hardeep Singh Nijjar was gunned down in June outside a temple near Vancouver.

Canadian national security agencies are investigating "credible allegations" that "agents" of India were involved in the death of a Sikh leader in June, Trudeau said.

A CDC report published Thursday found that ER visits linked to asthma rose 82% in New York in June due to smoke from the Canadian wildfires.

The historic wildfire season plaguing Canada is expected to persist in the coming weeks or even worsen, driven by human-caused climate change.

A large fire is threatening one of Canada's northernmost cities, Yellowknife, which has ordered a total evacuation of its 20,000 residents.

The Canadian first couple announced on social media that they will be separating after 18 years of marriage.

The couple, married since 2005, have three children together.

Canadian Prime Minister Justin Trudeau is splitting up with his wife, Sophie, according to the leader's Instagram page.

Environmental experts say that the Candian and U.S. governments need to take a more proactive approach at combating the root causes of growing wildfires.

From the Great Lakes to parts of the South and Mid-Atlantic, the smoke from Canadian wildfires have been swallowing skylines in major cities and leading to some of the worst air quality in the world.

States in the Midwest are experiencing air quality levels similar to those seen in the Northeast.

"Unhealthy" air conditions prompted Chicago Mayor Brandon Johnson to issue a statement warning people to “avoid strenuous activities and limit their time outdoors."

Smoke emissions from Canadian wildfires reaches highest recorded in country.

Canadian wildfire smoke is infiltrating the Midwest on Tuesday, and the air in Chicago has deteriorated to the Air Quality Index's "very unhealthy" category.

The smoke emissions from the wildfires burning in Canada has reached the highest-ever recorded in the country as plumes make their way across the Atlantic to Europe.

Authorities are responding to a "mass casualty collision" that occurred Thursday on a highway in Canada, Royal Canadian Mounted Police said.

The crash happened on the Trans-Canada Highway between a semi-truck and a bus.

Eerie timelapse condenses 45 minutes into 45 seconds, showing smoke from the ongoing Canadian wildfires overwhelming New York City, darkening the skies and obscuring buildings.

ABC News meteorologist Somara Theodore breaks down the extreme hazardous smoke in the Northeast.

Dangerous air quality will be a significant issue for millions of Americans to deal with early this week, as fires continue to spark throughout Canada.

More than 16,000 Nova Scotians are under evacuation orders as "unprecedented" wildfires rage across eastern Canada for a fifth day.

“Tobacco use continues to kill 48,000 Canadians each year,” Carolyn Bennett, minister of Mental Health and Addictions and Associate Minister of Health, said.

Authorities release new details as they try to track down leads after the precious cargo worth millions simply went missing.

Police are searching for suspects in what could be one of the biggest heists in Canada's history.

Police are searching for stolen cargo that contained 20 million Canadian dollars worth of gold and high-value goods stolen from Toronto Pearson International Airport.

The shipment container, which contained gold bars and other valuables, was stolen from Toronto’s Pearson Airport.

The new immigration policy is designed to stem the flow of asylum seekers from Central and South America.

The agreement will allow Canada to send more migrants who cross at unofficial ports of entry at America’s northern border back to the U.S.

ABC News senior national correspondent Terry Moran provides context on top issues President Joe Biden will discuss during a bilateral meeting with Canadian Prime Minister Justin Trudeau.

Niagara City Cruises says it will begin operations on Thursday, which marks the earliest opening in its history.