The Justice Department said Tuesday it will not appeal a federal district judge’s ruling that ended the nation’s federal mask mandate on public transit unless the Centers for Disease Control and Prevention believes the requirement is still necessary.

In a statement released a day after a Florida judge ended the sweeping mandate, which required face coverings on planes and trains and in transit hubs, Justice Department spokesman Anthony Coley said officials believe that the federal mask order was “a valid exercise of the authority Congress has given CDC to protect the public health.” He said it was “an important authority the Department will continue to work to preserve.”

Coley said the CDC had said it would continue to assess public health conditions, and if the agency determined a mandate was necessary for public health, the Justice Department would file an appeal.

As of Tuesday, the agency hadn’t made a determination, officials said.

The federal judge’s ruling did away with the last major vestige of federal pandemic rules and led to a mishmash of new locally created rules that reflected the nation’s ongoing divisions over how to battle the virus.

Major airlines and airports in places like Dallas, Atlanta, Los Angeles and Salt Lake City quickly switched to a mask-optional policy. Los Angeles County dropped its mandate for mass transit and a train conductor in New Jersey told commuters of their masks Tuesday: “Feel free to burn them at will.”

New York City, Chicago and Connecticut, however, continued to require masks for travelers.

The ride-sharing companies Lyft and Uber announced on their websites Tuesday that masks will now be optional while riding or driving.

Even Walt Disney World in Florida on Tuesday announced it was lifting its mask requirement for its monorail, buses and sky gondola.

For many, the news was welcome. A video showed some passengers on a Delta Air Lines flight cheering and applauding as they removed masks upon hearing the announcement they were now optional. One man happily twirled his mask on his finger.

However Brooke Tansley, a television producer and former Broadway performer, was incensed after boarding a flight with her 4-year-old and 8-month-old baby— neither old enough to be vaccinated — only to learn the mask mandate had ended mid-flight.

“Very very angry about this,” she said in a tweet, noting her baby was too young to wear a mask.

President Joe Biden went all-in on flexibility Tuesday when asked if Americans should mask up on planes.

“That’s up to them,” Biden declared during a visit to Portsmouth, New Hampshire. But the White House continues to require face coverings for those traveling with him on Air Force One, citing CDC guidance.

In Portland, Oregon, transit employees immediately began taking down “mask required” announcements and signs, but said it would likely take several days to remove everything.

The city joined Atlanta, Boston, Philadelphia, Washington, D.C., Kansas City, Missouri, and two of Alaska’s largest cities, Anchorage and Juneau, in making masking optional on mass transit.

Some passengers at Chicago’s Union Station said the rules were confusing. Amtrak dropped its requirement. The Chicago Transit Authority and Metra, the regional commuter rail service, kept the requirement at first but dropped it late Tuesday.

“It’s like this patchwork of different rules and enforcement of it,” said Erik Abderhalden, who wore a mask as he waited for a Metra train to his home in suburban Naperville. “I mean, it’s like Swiss cheese … there’s no uniformity and it seems pretty laissez-faire.”

Subway rider Cooper Klinges was pleased that New York City’s public transit system wasn’t following the trend and planned to keep its mask requirement in place. As he waited at a Brooklyn train station, he said he canceled a flight earlier this year over concerns about the virus.

“I don’t think we are out of the woods yet,” said Klinges, a teacher, citing concerns about the BA.2 omicron subvariant of the coronavirus. “It is still around. We have to still stick it out.”

The CDC had recently extended the mask mandate, which was set to expire Monday, until May 3 to allow more time to study the subvariant, which is now responsible for the vast majority of U.S. cases. But the court ruling puts that decision on hold.

After a winter surge fueled by the omicron variant that prompted record hospitalizations, the U.S. has seen a significant drop in virus spread in recent months that led most states and cities to drop mask mandates.

But several Northeast cities have seen a rise in hospitalizations in recent weeks, leading Philadelphia to bring back its mask mandate.