Arizona Governor Doug Ducey was ordered by the administration of United States President Joe Biden on Tuesday to halt its use of a fund to give anti-mask grants, according to media reports. The educational grants were reportedly only being directed towards schools that had not imposed a mask mandate.

The United States Treasury Department said in a letter to Ducey that the grants programme being run by the state of Arizona were “not a permissible use” of the funding, according to reports from Associated Press.

The letter from the Treasury Department, which is headed by Secretary Janet Yellen, reaffirmed that the condition set by the state of Arizona were undermining “evidence-based efforts to stop the spread of COVID-19” in the United States.

Governor Ducey, who is a member of the Republican party, had engineered the grant programme in August this year. The funding initiative, which was valued at $163 million, was created out of federal funding controlled by Ducey. The funds were only diverted towards schools that had not imposed a mask mandate during the COVID-19 pandemic, according to reports from Associated Press.

Arizona’s ban on mask mandates has received plenty of challenges so far. Education advocates have gone on to file a lawsuit over the ban on mask mandates and other laws in Arizona that restrict the authority of the local governments, school districts and educational institutions to impose requirements that aim to curb the spread of COVID-19.

Those policies conflict with guidance from the United States Centers for Disease Control and Prevention, which recommends universal mask wearing for students and teachers in the classroom. Deputy Treasury Secretary Wally Adeyemo asked Arizona officials to explain how it will remedy the problem within 30 days.