A federal judge struck down President Joe Biden’s extension of the mask mandate on interstate public transportation on Monday after it had been extended to May 3.

Judge Kathryn Kimball Mizelle, an appointee of former President Donald Trump, ruled that the Biden administration and the Centers of Disease Control and Prevention (CDC) overstepped their authority by extending the mask mandate. She said that the CDC in particular failed to explain its decision for making the move and ended up overreaching.

The mask mandate for public transit, which includes airplanes and interstate buses, has been a source of consternation for Republican Party politicians and members of industry. There was no immediate word from the White House about whether it plans to appeal the ruling.

In late March, 20 Republican-led states sued the Biden administration in a bid to overturn the mask mandate. They too argued the CDC overstepped its authority in maintaining the mandate and accused the Biden administration of interfering with their own laws against mask mandates.

The airline industry similarly urged the White House to do away with the mask mandate. On March 23, a group of airline executives penned a letter to Biden arguing that the current COVID-19 situation did not justify further continuation of the mandate.

The injunction comes at a time when concern is building about the highly-transmissible COVID-19 BA.2 “stealth subvariant.” Several states have already warned that case numbers are inching higher and it has prompted some public health agencies to reinstitute preventative measures. For example, Philadelphia reinstated a general mask mandate that has already been met with court challenges.

Judge Mizelle’s order was also met with skepticism by several legal experts, who took issue with her decision. Steve Vladeck, a law professor at the University of Texas, described it as both a “big deal” and a “truly preposterous” ruling for her argument against the CDC’s policies.

“The CDC’s statutory authority is specifically directed at preventing the spread of communicable diseases across state lines,” Vladeck wrote on Twitter. “Where else is such spread more likely to occur than transport hubs like airports?”