WASHINGTON - D.C. Mayor Muriel Bowser announced on Thursday that mask mandates are once again in effect indoors in the nation’s capital for everyone over the age of 2 – regardless of COVID-19 vaccination status.READ MORE: DC professional sports franchises continue to struggle with COVID-19, vaccinationsThe mandate will go into effect on July 31 at 5 a.m.READ MORE: Smithsonian to require masks indoors once again as COVID-19 delta variant spreadsThe mayor’s announcement comes in the wake of new Centers for Disease Control guidelines regarding masks.Download the FOX 5 DC News App for Local Breaking News and WeatherThe District is currently ranked at "substantial" for its rate of transmission as the delta variant of the novel coronavirus spread.