(CNN) A federal judge on Wednesday put on hold for five weeks his ruling striking down the controversial Title 42 immigration policy, a Trump-era rule that's allowed US authorities to expel more than 1 million migrants who crossed the US-Mexico border.
US District Judge Emmet Sullivan said in the new order that he was granting the Biden administration's request for a stay with "GREAT RELUCTANCE."
The ruling striking down Title 42 will be now on hold until midnight December 21.
Sullivan's ruling on Tuesday will leave the Biden administration without one of the key tools it had deployed to address the thousands of migrants arriving at the border on a daily basis and could restore access to asylum for arriving migrants.
The authority -- which was heavily criticized by public health experts and immigrant advocates -- had largely barred asylum at the US-Mexico border, marking an unprecedented departure from traditional protocol. Its end could now restore access to asylum for arriving migrants, allowing them to enter the US and make their case in immigration court.
Sullivan had found the Title 42 order to be "arbitrary and capricious in violation of the Administrative Procedure Act."
Prior to Title 42, all migrants arrested at the border were processed under immigration law. Thousands of migrants sent back to Mexico have been waiting along the border in shelters. Officials have previously raised concerns about what the end of Title 42 may portend, given limited resources and a high number of people trying to enter the country.
Sullivan's ruling also comes on the heels of the resignation of US Customs and Border Protection Commissioner Chris Magnus, who had been asked to resign by Alejandro Mayorkas last week. CBP Deputy Commissioner Troy Miller is now serving as the acting commissioner.
CNN has reached out to the White House and Justice Department for comment.
Sullivan faulted the US Centers for Disease Control and Prevention, which issued the public health order, for "its decision to ignore the harm that could be caused" by issuing the policy. He said the CDC also failed to consider alternative approaches, such as letting migrants self-quarantine in homes of US-based friends, family, or shelters. The agency, he said, should have reexamined its approach when vaccines and tests became widely available.
"With regard to whether defendants could have 'ramped up vaccinations, outdoor processing, and all other available public health measures,'... the court finds the CDC failed to articulate a satisfactory explanation for why such measures were not feasible," Sullivan wrote.
The judge also concluded that the policy did not rationally serve its purpose, given that Covid-19 was already widespread throughout the United States when the policy was rolled out.
"Title 42 was never about public health, and this ruling finally ends the charade of using Title 42 to bar desperate asylum seekers from even getting a hearing," American Civil Liberties Union attorney Lee Gelernt, who argued the case, said in a statement.
The injunction request came from the ACLU, along with other immigrant advocacy groups, involves all demographics, including single adults and families. Unaccompanied children were already exempt from the order.
The ACLU does not oppose the Biden administration's request for a stay of Tuesday's ruling through December 21, the administration noted in their filing.
In a statement following the ruling, the Department of Homeland Security said that, if granted, "the delay in implementation of the court's order will allow the government to prepare for an orderly transition to new policies at the border."
The department added that it would continue to enforce immigration laws at the border, work with other countries to take action against smuggling networks and "address the root causes of irregular migration."
The public health authority was invoked at the onset of the coronavirus pandemic and has been criticized by immigrant advocates, attorneys and health experts who argue it has no health basis and puts migrants in harm's way.
Sullivan had previously blocked the Biden administration from expelling migrant families with children apprehended at the US-Mexico border.
Earlier this year, in anticipation of lifting Title 42 and under pressure from lawmakers, the Department of Homeland Security released a 20-page plan to manage a potential increase of migrants at the border. A separate federal judge struck down the administration's intent to end Title 42 at the time.
The CDC said at the time it's no longer necessary given current public health conditions and the increased availability of vaccines and treatments for Covid-19.
But in May, a federal judge in Louisiana blocked the Biden administration from ending Title 42.
Since that court order, the administration has continued to use Title 42 and most recently, expanding it to include Venezuelan migrants who have arrived at the US southern border in large numbers.
In October, there were more than 204,000 arrests along the US southern border and over 78,400 expulsions under Title 42, according to CBP data.
This story has been updated with additional details.