The fast-spreading variant seems to have broken through China’s Covid defences as the country battles its worst outbreak since the virus first emerged there in late 2019.
On Wednesday, China reported its highest daily number of local coronavirus cases in months at 71. The number of new cases has been increasing for five consecutive days since July 30.
Mass testing and contact tracing campaigns have uncovered a trail of Delta variant infections.
The highly transmissible Delta variant, which was first identified in India, has been detected in more than a dozen Chinese cities, including capital Beijing, since late July.
China has reported 485 locally transmitted cases with symptoms between July 20 and August 3, although it’s not immediately clear how many involve the Delta variant.
As of early Wednesday, 17 provinces, regions and municipalities have reported locally transmitted cases both with symptoms and without.
Chinese officials admit that curbing the latest outbreak will be much harder than the others, owing to the fast and asymptomatic spread of the Delta variant.
What led to the outbreak
The initial Delta infection arrived via an overseas flight from Moscow into the eastern Chinese city of Nanjing in mid-July.
Seven passengers on the flight were infected with the variant. It subsequently spread on to a group of airport cleaning staff with nine of them testing positive on July 20.
Their infections spread quickly among people who entered the airport, a major transportation hub.
Within weeks, cases popped up as far away as Hainan island in China’s south, 1,900 kilometers (1,180 miles) from Nanjing.
Mass testing, restrictions
China went into an overdrive following the latest outbreak of the Delta variant, ordering mass testing and clamping down cities.
Nanjing and Yangzhou in eastern Jiangsu province, where the majority of China’s local Delta cases have been reported since July 20, have suspended domestic flights, long-distance shuttle buses, taxis and ride-hailing vehicles from entering and leaving the two cities, and suspended some bus services.
In Wuhan, officials are this week testing all of the city’s 12 million residents over three days after uncovering the first locally transmitted infections since mid-2020, and shut parts of an economic development and innovation zone.
Many cities with Covid-19 cases have closed tourist sites and shuttered entertainment venues. The southern tourist city of Zhangjiajie has banned residents and travellers from leaving.
Meanwhile, in Nanjing millions of residents have had to participate in four rounds of testing.
Jiang, who works in real estate, said she understood the need for testing, but was still critical of officials for failing to control the latest outbreak. “The leaders are actually wasting resources and everyone’s time,” she said.
City sealed off
Zhangjiajie, a city with a population of about 1.5 million, sealed residential communities last week, preventing people from leaving their homes.
In a subsequent order on Tuesday, officials said no one, whether tourist or resident, could leave the city.
The city itself has only recorded 19 cases since last week, three of which were people with no symptoms, which are counted separately.
However, individual cases linked to Zhangjiajie’s outbreak have spread to at least five provinces, according to the Shanghai government-owned newspaper the Paper.
Far higher numbers were reported in Yangzhou, a city next to Nanjing, which has recorded 126 cases as of Tuesday.
(With inputs from agencies)