The Centers for Disease Control and Prevention’s mask mandate was struck down by a federal judge Monday who ruled that the policy was unlawful. The mandate, which CNN reports has been in place since the pandemic began in 2020 and was recently extended through May 3, enforces mask-wearing on public transportation services like airplanes and trains. U.S. District Judge Kathryn Kimball Mizelle, who was appointed by former President Donald Trump, determined that the scope of the mandate was beyond the legal purview of the CDC. “The Mask Mandate is best understood not as sanitation, but as an exercise of the CDC's power to conditionally release individuals to travel despite concerns that they may spread a communicable disease (and to detain or partially quarantine those who refuse),” she wrote in her ruling. “But the power to conditionally release and detain is ordinarily limited to individuals entering the United States from a foreign country.” It remains unclear when Mizelle’s ruling could go into effect at transportation hubs across the country.