The debut of Polish star Robert Lewandowski in Major League Soccer (MLS) has been postponed after the match between his new team Chicago Fire and Vancouver Whitecaps, originally scheduled for Thursday, was delayed due to poor air quality caused by wildfires.

Smoke from wildfires raging in the Canadian province of Ontario spread across the United States on Thursday, causing severe air pollution in border states, particularly Minnesota, Wisconsin, Michigan, and Illinois.

Chicago Fire announced in a statement that the match, which was scheduled at their home stadium, has been postponed to October 6.

The club said: 'The decision to reschedule the match was made after close consultations with local health experts, Major League Soccer, Vancouver Whitecaps, and the city of Chicago.'

Around 40,000 spectators were expected at Soldier Field for the match, which was part of the league's resumption after its break during the World Cup.

Lewandowski, who joined from Barcelona after helping the Catalan club win La Liga last month, was expected to make his MLS debut in a match that would have pitted him against his former Bayern Munich teammate Thomas Müller.

The next opportunity for Poland's all-time top scorer to play his first MLS match will be next Wednesday against Inter Miami, where Argentine Lionel Messi is not expected to participate due to his involvement in the World Cup final on Sunday.

Illinois was among the U.S. states most affected by the wildfire smoke.

A smoky haze also hung over the New York City area, where Argentina, led by Messi, is scheduled to face Spain in the World Cup final on Sunday.

New York state authorities warned of high levels of fine particles from the fires, stating that being outdoors would be 'unhealthy'.