More stringent rules for face coverings were announced Monday by Gov. Newsom.
With few exceptions, all people must wear a mask whenever they're outside of their home in the state.
Children under 2 years old and people with medical conditions are exempt from the requirements. People may als take off masks when they are alone, such as driving a car or working in an office.
Masks are not required when eating or drinking, but people are expected to maintain a safe social distance from others.
"The use of face coverings by everyone can limit the release of infected droplets when talking, coughing, sneezing, singing, exercising, shouting, or other forms of increased respiration, and they can also reinforce physical distancing by signaling the need to remain apart," the Department of Publoch Health says.
More details are avaialbe on the state Department of Public Health's website.
The requirements are similar to what Bay Area counties imposed on residents and visitors earlier in the pandemic.
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Newesom announced the new rule on the day that much of California was thrust backward into the most restrictive tier as coronavirus cases sharply increased.
He also floated the idea of imposing a curfew if the case numbers are not brought under control.
Yet, Newsom's own compliance with safety measures has come under criticism. He apologized for attending a birthday party with a group at the French Laundry in Yountville that conflicted with his repeated pleas for residents to avoid social gatherings.