One of the last remaining nationwide COVID-19 restrictions in the US has been overturned, with masks no longer required on public transport.
Passengers ripped off their face coverings and cheered after the mask mandate was quashed by a federal judge on Tuesday, but not everyone was celebrating.
Here's why.
Mask mandate overturned
While the US government eased most indoor mask rules last month, there was still a national requirement mandating the use of masks on mass transit services, including planes, trains, ride-sharing and public transport.
And in light of the rapid spread of the Omicron BA.2 subvariant, the US Centers for Disease Control and Prevention (CDC) last week extended the mandate until May 3.
But on Tuesday, US District Judge Kathryn Kimball Mizelle threw out the mandate, ruling it unlawful.
It was the outcome of a lawsuit filed in Florida last year asking the court to overturn the national order.
Judge Kimball Mizelle said the CDC overstepped its authority by issuing the original health order, saying it was fatally flawed because the CDC didn't follow proper rule-making procedures.
Airlines end mask rule mid-flight
The ruling gave airports, mass transit systems, airlines and ride-hailing services the option to keep mask rules or ditch them entirely.
Many public transport authorities across the US updated their rules to make masks optional, but not in New York — the Metropolitan Transportation Authority's spokesperson said masks were still mandatory on trains and busses.
Ride-sharing companies Lyft and Uber announced on their websites that masks were only optional for drivers and passengers.
And as soon as the Transportation Security Administration said it would no longer enforce the mandate, major US airlines including American Airlines, United Airlines and Delta Air ended their mask rules.
In some cases, this happened mid-flight.
Social media footage shows passengers and flight crew cheering and clapping after the rule change was announced, with many choosing to remove their masks.
But not everyone was celebrating
Some passengers said they were caught off guard by the rule change and wouldn't have chosen to fly had they known masks weren't going to be required.
Others raised concerns about immunocompromised people and children under five, who are not yet able to be vaccinated:
The US now averages about 35,000 confirmed COVID-19 cases a day.
That's down from the January peak of more than 800,000 during the Omicron surge, but up slightly from the lows of about 26,000 a month ago
However, it's likely the true number of cases is higher than official figures due to cases going undiagnosed and people not reporting their positive at-home test results to public health authorities.
And the White House says keep wearing masks
White House press secretary Jen Psaki said the ruling was "disappointing".
"Public health decisions shouldn't be made by the courts — they should be made by public health experts," she said.
She said the CDC was reviewing the decision and that people should keep wearing masks on public transport even if they were not legally required to.
When asked, shortly after Ms Psaki's White House press conference, whether people should keep wearing masks on planes, US President Joe Biden said: "It's up to them."
What happens now?
The White House could appeal against the ruling.
But the CDC must assess the current outbreak first.
"If CDC concludes that a mandatory order remains necessary for the public's health after that assessment, the Department of Justice will appeal the district court's decision," the Justice Department said in a statement.
ABC with wires
