San Francisco, Nov 20 (IANS): California Governor Gavin Newsom has announced a mandatory overnight stay-at-home order limiting non-essential work, movement and gatherings in most areas of the state to curb the spread of Covid-19.

The order requires generally that non-essential work, movement and gatherings stop between 10 p.m. and 5 a.m. in counties under the purple tier, where Covid-19 transmission rates are the highest, reports Xinhua news agency.

The order will take effect at 10 p.m. on November 21 and remain until 5 a.m. on December 21, according to the office of the governor.

"The virus is spreading at a pace we haven't seen since the start of this pandemic and the next several days and weeks will be critical to stop the surge. We are sounding the alarm," Governor Newsom said in a statement on Thursday.

"It is crucial that we act to decrease transmission and slow hospitalizations before the death count surges. We've done it before and we must do it again," he added.

The order is designed to reduce opportunities for disease transmission.

Activities conducted during 10 p.m. to 5 a.m. are often non-essential and more likely related to social activities and gatherings that have a higher likelihood of leading to reduced inhibition and reduced likelihood for adherence to safety measures like wearing a face covering and maintaining physical distance.

A total of 41 of 58 California counties, comprising over 94 per cent of the state's population of around 40 million, are now in the purple tier.

The state has so far reported more than 1.08 million confirmed coronavirus cases with 18,516 deaths.