In Shanghai, home to the world’s busiest port, a wave of quarantine restrictions due to the COVID-19 outbreak has forced millions of people (about 3 times the number living in New York City) to stay self-isolated at home and undergo mass testing for the virus, CNBC writes.

Since the coronavirus began rising in late February, Shanghai has tried to control the outbreak with targeted quarantine restrictions in different neighborhoods. But then the huge city, which is the country’s center of transportation, manufacturing, finance and trade, decided to impose a two-stage quarantine in late March, which soon spread to all districts, forcing people to stay permanently in their apartments.

Officially, the number of permanent residents in Shanghai in 2020 was 24.9 million, slightly less than Australia’s population of 25.7 million, according to the World Bank, but just 1.8 percent of the 1.41 billion people in all of China.

If we compare Shanghai to American cities, its population number is 3 times that of New York City (which has 8.3 million people), the largest city in the US, which means that the 280,120 COVID-19 cases reported by Shanghai as of last Thursday for the latest outbreak of the virus represent only 1.1% of the city’s population.

Note that Shanghai’s GDP is quite large as well, with 4.32 trillion yuan ($680.31 billion) in 2021, more than Sweden’s ($660.92 billion), according to the IMF.

But still, Shanghai’s GDP in 2021 was only 3.8% of China’s national GDP of 114.37 trillion yuan. Among other things, Shanghai is a global trade center: it is located at the mouth of the Yangtze River, one of China’s two major rivers, it is also home to the world’s busiest port, and Shanghai Pudong Airport is the third busiest cargo airport in the world after Memphis, Tennessee and Hong Kong airports. Overall, Shanghai accounted for 7.3% of China’s exports and 14.4% of imports in 2021.

Shanghai is China’s largest manufacturing and corporate center: it is home to semiconductor manufacturers SMIC, Hua Hong and Universal Scientific Industrial, many automakers – SAIC Motor, SAIC’s joint ventures with Volkswagen (ETR: VOWG) and GM, Nio, Tesla (NASDAQ:TSLA) and Ford, headquarters or major centers of operations of multinational corporations – Apple (NASDAQ:AAPL), L’Oreal, Samsung Electronics, P&G, LVMH , Nike, Panasonic, Philips, Johnson & Johnson and General Electric, shipbuilding companies – Jiangnan, Zhonghua and Waigaoqiao.

That the city is the world’s largest financial center is evidenced by the fact that the Shanghai Stock Exchange is the third largest by market capitalization after the New York Stock Exchange and Nasdaq, and that U.S. mutual fund giant Vanguard has announced a plan to move its headquarters from Hong Kong to Shanghai in 2020; Fidelity’s financial business in China is based in Shanghai, as are the Bridgewater China operations of U.S. billionaire Ray Dalio.

Among other things, Shanghai is also a major consumer center: while the average disposable income in China is 35,128 yuan ($5,531), in this city it is 78,027 yuan ($12,288), and average consumer spending here is 48,879 yuan, also double the national average (24,100 yuan).

US wholesaler Costco has chosen Shanghai to open its first store in mainland China in 2019.

The fact that Shanghai is also a cultural and scientific center is evidenced by the fact that 3 of China’s top 20 universities are located here.

Meanwhile, the number of foreigners living in Shanghai fell to 163,954 in 2020, down 21% from a decade earlier.

The total number of foreigners in the country grew by about 40% over the 10 years to 1.4 million, or about 0.1% of China’s population.