WASHINGTON—Masks will be required indoors in Washington for everyone 2 years and older starting Saturday, Mayor Muriel Bowser said on Thursday, regardless of whether they have been vaccinated against the COVID-19 virus. The mandate will put the nation’s capital in line with updated guidance that the Centers for Disease Control and Prevention (CDC) released this week. Many federal government institutions in Washington and its suburbs have already implemented similar mask requirements. In addition, the Smithsonian said it would reimpose mask requirements at its museums that line the National Mall and other indoor venues for visitors 2 years and older beginning on Friday “regardless of vaccination status.” Face coverings may be removed while eating or drinking in designated areas, it said in a statement on Thursday. By the beginning of July, Washington had hit its lowest rate of community spread of COVID-19 since the global pandemic began a year and a …