Racing at Belmont Park was canceled and the Washington Nationals' home game against the Arizona Diamondbacks was postponed Thursday due to poor air quality from wildfires in Canada.

It's the second straight day the continuing fires north of the border have impacted sports in the Northeastern United States. The New York Giants also called off a practice Thursday scheduled to be held in East Rutherford, N.J.

The New York Racing Association canceled live racing at Belmont Park two days before the facility is scheduled to host the final leg of the Triple Crown with the Belmont Stakes.

As previously announced, morning training was canceled Thursday at both Saratoga Race Course and Belmont Park. The conditions that necessitated the cancelation of training are likely to persist this afternoon and into the evening, according to the NYRA, and a twilight racing program that would kick off the 2023 Belmont Stakes Racing Festival has been cancelled.

"Based on current forecast models and consultation with our external weather services, we remain optimistic that we will see an improvement in air quality on Friday," NYRA President & CEO David O'Rourke said in a statement.

The Diamondbacks-Nationals contest, which was rescheduled for June 22 at Nationals Park, was the third game postponed by Major League Baseball over the last two days. The New York Yankees and Philadelphia Phillies had their home games postponed Wednesday.

"This postponement was determined following conversations throughout the day with medical and weather experts and the two impacted Clubs regarding clearly hazardous air quality conditions in Washington, D.C.," MLB said in a statement.

Nationals manager Dave Martinez, speaking to reporters before the postponement was announced, said he hoped MLB would make the right decision for both players and fans while adding that he walked his dogs Thursday morning and it "wasn't good."

The game in New York between the White Sox and Yankees was rescheduled as part of a doubleheader Thursday, and the Phillies' game against the Tigers also was reset for Thursday, originally a day off for both teams.

MLB was continuing to monitor the air quality in both cities, but as of Thursday morning, the doubleheader in the Bronx at 4:05 p.m. ET and the contest in Philadelphia at 6:05 ET both were still scheduled to be played.

A National Women's Soccer League game in New Jersey and an indoor WNBA game set for Brooklyn were also called off Wednesday amid hazy conditions that have raised alarms from health authorities.

The Giants' practice Friday also is likely to be canceled, according to coach Brian Daboll. The New York Jets still planned to practice Thursday and Friday at their indoor facility in Florham Park, N.J., some 30 miles west of East Rutherford.

"It is [wild times]," New York offensive coordinator Mike Kafka said minutes after practice was called off. "Have not [seen anything like it] -- have not. Wednesday it was orange [outside]."

The air quality index outdoors in East Rutherford was 198 at 10 a.m. ET on Thursday -- a number that is considered unhealthy. An AQI of 200 and above is very unhealthy.

ESPN's Jordan Raanan, The Associated Press and Reuters contributed to this report.