Smoke from Canadian wildfires poured into the U.S. East Coast and Midwest on Wednesday, covering the capitals of both nations in an unhealthy haze, holding up flights at major airports, postponing Major League Baseball games and prompting people to fish out pandemic-era face masks.While Canadian officials asked other countries for additional help fighting more than 400 blazes nationwide that already have displaced 20,000 people, air quality with what the U.S. rates as hazardous levels of pollution extended into central New York, northeastern Pennsylvania and, later, the New York metropolitan area. Massive tongues of unhealthy air extended as far as North Carolina and Indiana, affecting millions of people.New York Gov. Kathy Hochul has issued a recommendation for people in New York to cancel all outdoor activities."You don't need to go out and run tonight, you don't need to go out and take a walk, you don't need to push the baby in the stroller, this is not a safe time to do that," said the Governor.Major League Baseball put off games in New York and Philadelphia, and even an indoor WNBA game in Brooklyn was called off. The smoke even affected Broadway, where “Killing Eve” star Jodie Comer had difficulty breathing and left the matinee after 10 minutes; the show restarted with an understudy, show publicists said.Schools in multiple states canceled sports and other outdoor activities, shifting recess inside. Live horse racing was canceled Wednesday and Thursday at Delaware Park in Wilmington. Organizers of Global Running Day, a virtual 5K, advised participants to adjust their plans according to air quality.New Jersey closed state offices early, and some political demonstrations in spots from Manhattan to Harrisburg, Pennsylvania, were moved indoors or postponed. Striking Hollywood writers were pulled off picket lines in the New York metropolitan area.Canadian officials say this is shaping up to be the nation's worst wildfire season ever. It started early on drier-than-usual ground and accelerated very quickly, exhausting firefighting resources across the country, fire and environmental officials said.Smoke from the blazes in various parts of the country has been lapping into the U.S. since last month but intensified with recent fires in Quebec, where about 100 were considered out of control Wednesday — which, unsettlingly, was national Clean Air Day in Canada.The Federal Aviation Administration paused some flights bound for LaGuardia Airport and slowed planes to Newark Liberty and Philadelphia because the smoke was limiting visibility. It also contributed to delayed arrivals at Dulles International Airport outside Washington.