41NBC News | WMGT-DT July 28, 2021 Centers for Disease Control and Prevention mask. Photo courtesy of MGN. New guidance from the federal government set off a cascade of mask rules across the nation Wednesday as cities, states, schools and businesses raced to restore mandates and others pushed back against the guidelines at a time when Americans are exhausted and confused over constantly shifting pandemic measures. Nevada and Kansas City, Missouri, were among the locations that moved swiftly to re-impose indoor mask requirements following Tuesday’s announcement from the Centers for Disease Control and Prevention. But governors in Arizona, Pennsylvania and South Carolina said they would resist reversing course.