DC residents must wear masks indoors beginning Saturday, July 31, at 5 a.m.

Citing the escalating spread of the Delta variant, the District of Columbia is reinstating its indoor mask mandate this week.

In a press conference Thursday, Mayor Muriel Bowser announced District residents over the age of 2 are required to wear face coverings indoors despite vaccination status. The change is effective Saturday, July 31 at 5 a.m.

"I know that DC residents have been very closely following the public health guidelines and they will embrace this, our businesses will embrace it, and we will continue to do what is necessary to keep DC safe," Mayor Bowser said in regards to the new policy.

The decision bounces off the Center for Disease Control and Prevention's latest update reversing the course on mask usage. Due to the contagiousness of the Delta variant, the organization recommends individuals in areas facing "substantial or high transmission" of the virus continue wearing masks in public spaces. Additionally, face coverings are highly encouraged for those who are immunocompromised or have members in their household who are.

LIVE: Situational Update July 29. https://t.co/AaljuLo0Ct

— Mayor Muriel Bowser (@MayorBowser) July 29, 2021

So what does "substantial" or "high" transmission refer to in this context? According to the CDC, any place producing 50 new cases out of 100,000 people in a week would constitute substantial or high spread. Director of DC Health Dr. LaQuandra Nesbitt reports the city "has experienced a four-fold increase in its daily case rate since the beginning of July," with a recent total averaging 56 cases per day. As of July 27, 50,268 positive cases and 1,146 deaths have been recorded during the pandemic.

Health officials urge those who haven't to get the vaccine and continue wearing masks in public to prevent further spread of the virus.

"Wearing a mask in indoor public settings provides an additional layer of protection for those who are fully vaccinated—and continues to be one of the key ways to protect those who cannot be vaccinated, namely young children," Dr. Nesbitt added. "If you are eligible to be vaccinated, we strongly encourage you to do so immediately to minimize the risk of disease, hospitalization, or death.”

What do you think about DC's decision to require masks indoors? Share your thoughts with us in the comments.