Protests in solidarity with people in China are also taking place elsewhere this evening.
In London, several hundred people have been protesting outside the Chinese embassy.
Some laid flowers and lit candles in memory of the victims who died in an apartment block fire in the western city of Urumqi earlier this week.
Many in China have blamed strict Covid rules for their deaths, though Chinese authorities have denied this.
China is no longer imposing a national lockdown and has relaxed a number of previous measures.
However, the central government is telling local authorities to impose strict lockdowns in their areas when they detect a Covid-19 outbreak – even if only a handful of cases are found.
Mass testing is being carried out in places where cases have been reported. People found to have Covid-19 are isolated at home or placed under quarantine at a government-supervised facility.
Businesses and schools are closed, and so are all shops except for those selling food.
It is one of the toughest anti-Covid regimes in the world and lockdowns last until no new infections are reported.
Tens of millions of people have been living under some kind of lockdown since the latest wave of Covid-19.
Guangzhou, a southern city of nearly 19 million people, recently ordered a five-day lockdown for Baiyun, its most populous district.