Last month, leaders of major airlines — including Delta, American Airlines and United Airlines — called on the Biden administration to let the mask mandate expire on planes and at airports in a joint letter.

Judge Mizelle also faulted the agency for issuing the warrant under emergency procedures without delaying public comment on the proposal – dismissing the idea that there was no time for it since the pandemic was then already a year old.

“The CDC issued the warrant in February 2021, nearly two weeks after the president called for a warrant, 11 months after the president declared Covid-19 a national emergency, and nearly 13 months since the secretary at Health and Human Services has declared a public health emergency,” she noted. “This story suggests that the CDC itself did not find the passage of time particularly serious.”

Pointing out that 11 months had passed between when “the president” declared a national emergency and the agency imposed the mandate, Judge Mizelle did not address the fact that another administration had just take office.

On Sunday, there were an average of more than 37,000 new cases per day, a 39% increase from two weeks ago, according to a New York Times database.

Although the figure remains well below the peak of the winter surge caused by the Omicron variant, experts believe that new cases are increasingly underestimated with the rise in home testing. Many people vaccinated and given booster shots did not become seriously ill after contracting the Omicron variant. And because home testing has become so widely available and results are rarely reported, the number of cases recorded by federal and local authorities in many states has been a low estimate or undercount.

The removal of the travel mask requirement at this time was “very, very concerning,” said Saskia Popescu, an infectious disease epidemiologist and assistant professor at George Mason University.

“We’re definitely starting to see an upward trend in cases,” she said. ‘My concern is that we may see what has happened in the UK, where they have reduced restrictions significantly and seen a significant increase, and that will contribute to the increase in numbers.’

The report was provided by Noah Weiland and Madeleine Ngo of Washington, and Ana Ley, Adel Hassan, Niraj Chokshi Roni Caryn Rabin from New York.