The US Department of Justice (DOJ) Wednesday filed a notice of appeal of a judge’s decision to end the mask mandate on public transportation and airplane after the Centers for Disease Control and Prevention (CDC) said the measure was still needed.

A US district judge vacated the government’s traveler mask mandate on April 13 because the mandate exceeded the CDC’s statutory authority under the Public Health Services Act. The judge held the mask mandate was not directly related to sanitation. The day after the decision, the DOJ said it would appeal the decision if the CDC deemed the mandate necessary. The CDC on Wednesday requested the DOJ to appeal because it determined the mandate “remains necessary for the public health.”

The CDC said their priority was to protect the public health of our nation. Commenting on the decision, the CDC said: “As we have said before, wearing masks is most beneficial in crowded or poorly ventilated locations, such as the transportation corridor.”

DOJ spokesman Anthony Coley agreed with the CDC’s statement, asserting that the DOJ “continues to believe that the order requiring masking in the transportation corridor is a valid exercise of the authority Congress has given CDC to protect the public health. That is an important authority the department will continue to work to preserve.”

For right now, public transportation providers can continue to decide whether to enforce a mask mandate since the DOJ did not request a stay from the court to reinstate the mask mandate.