China has imposed its most widespread restrictions since the start of the coronavirus pandemic last year, placing travel restrictions on about 23m people and putting some areas into lockdown after a sudden rise in cases. Beijing reported that China’s total symptomatic cases had exceeded 100 on Wednesday, the biggest outbreak since last July. Ninety of the new infections were in Hebei province, next to Beijing.

Residents of Shijiazhuang, Xingtai and Lanfang, three cities in the province, have been unable to leave since Tuesday. More than 10 local governments across the country, including in Beijing, Shanghai and Guangdong, have also asked residents to suspend all but essential travel. Shijiazhuang started mass testing for Covid-19 on Tuesday for all residents for the second time this month. The first round of testing found 354 positive cases among 10m people.

Authorities want to limit the chances of spreading the virus during the lunar new year break next month. The seven-day national holiday is usually the world’s largest annual mass migration when hundreds of millions of city workers return to their family homes in the provinces. The new restrictions have been imposed ahead of a visit by a World Health Organization team, that will arrive in China on Thursday to investigate the origins of Covid-19 after a series of delays over visa approvals. Beijing has been keen to propagate the narrative that the virus originated outside of China, despite the first mass outbreak occurring in Wuhan.

Local governments have not indicated punishments for those who contravene the rules, but state-owned enterprises and government agencies have implemented penalties for employees. Two Beijing SOE employees told the Financial Times their pay would be docked if they left the city. Another said they had to write a note of self-criticism after leaving Beijing without telling their manager.