In a major U-turn late on Sunday night, authorities in the Chinese financial hub of Shanghai ordered a vast swathe of the city into a lockdown from Monday to try to contain the spread of a coronavirus outbreak. The city government said that from 5am the Pudong New Area – a 1,200 sq km (465 sq mile) zone on the eastern bank of the Huangpu River and home to about 5.7 million people – would lock down for four days of mass testing. The districts of Jinshan, Fengxian, Chongming and part of Minhang must also to go into lockdown from 5am Monday. After that, Puxi, on the western bank of Huangpu River, will go into lockdown for four days. Residents will be confined to their neighbourhoods and all public transport, including buses, metro lines, taxis and ferries as well as privately owned vehicles will be barred from travelling between the two areas. The surprise decision came after repeated assurances by city officials that Shanghai would not go into a lockdown. On March 15, Gu Honghui, a deputy secretary general of the Shanghai municipal government, said there was no need to take such action . Until this month, the city of 25 million had been held up as a model for others, recording just 400 infections and seven deaths in the two years since the coronavirus erupted in Wuhan. But the city has been struggling to contain the spread of the Omicron variant in the last few weeks. As of Sunday, Shanghai had reported nearly 11,500 Covid-19 infections since the outbreak began on March 1, the bulk of which were asymptomatic. The orders are set to disrupt operations at key facilities, from the Yangshan container port and Pudong International Airport to Tesla’s Gigafactory and production centres owned by SMIC, China’s biggest chip maker. The local authorities did not say whether the Pudong airport and Yangshan port would be shut for the lockdown. But the city government said all companies based in Pudong would be allowed to operate either under the “closed loop” system or on a work-from-home basis. Under a “closed loop”, factories are sealed off with only limited staff working and living inside the areas. The area is also home to Shanghai Tower, the country’s tallest super skyscraper; the world’s largest Disney amusement park; and a Nasdaq-like tech board, known as the Star Market. Frustration, fears of citywide lockdown as Omicron tests Shanghai Gao Shen, an independent analyst in Shanghai, said the lockdown would inflict “huge economic costs since Shanghai is the Chinese mainland’s gateway city”. “To lock down Pudong and Puxi one by one, the city government is still trying its best to minimise the impact on the local and national economies,” Gao said.