DENVER (AP) — Gov. Jared Polis extended a statewide mask mandate for another 30 days on Sunday, but loosened face covering requirements for groups of people who are vaccinated against COVID-19.

Under the new executive order, people gathering inside in groups of 10 or more are no longer required to wear masks if at least 80% of the group is vaccinated. The order states people must show proof of vaccination, but it does not elaborate on what proof is considered acceptable.

In April, Polis lifted mask requirements in most indoor settings in counties where the threat of COVID-19 was the lowest — the counties that fall under “Level Green” on the state’s scale.

In counties with higher rates of COVID-19, masks must be worn in all public indoor spaces when 10 or more unvaccinated individuals or individuals of unknown vaccination status are present.

Residents statewide are still required to wear masks at schools, child care centers, indoor children’s camps, public-facing state government facilities, correctional facilities and health care settings.

About 1.9 million people in Colorado are fully vaccinated and 2.6 million people have received at least one dose, according to state data.