Starting Friday, Idaho, Maine, Maryland, Michigan, Minnesota, Montana and West Virginia will move up from the city’s “yellow” tier to the “orange” one, according to a Chicago Department of Public Health news release. Travelers coming from the latter tier, which will include 26 states, must quarantine for 10 days or test negative for coronavirus no more than 72 hours before arriving. People can avoid either requirement if they have been fully vaccinated at least two weeks earlier.