Initially, there had been separate measures for the eastern and western sides, but the whole city is now subject to indefinite restrictions, reports BBC.

Shanghai is the largest city in the country to be put under lockdown.

The city, considered as a crucial financial hub, has been battling COVID-19 infection surge for more than a month now.

The authorities reacted after new cases rose to more than 13,000 a day, although the numbers are not high by some international standards, reports BBC.

Residents in some areas of the city said the strict policy meant no-one was allowed to leave their housing compounds, not even to collect essential provisions, the British media reported.

Social media here is full of angry residents complaining that they can't order food because the delivery system is clogged up, BBC reported.

The Chinese mainland reported 1,173 new locally-transmitted Covid-19 infections on Monday, the National Health Commission said Tuesday.

Of the local confirmed cases reported Monday, 792 were in Jilin, 268 in Shanghai, and 17 in Heilongjiang.

Besides, a total of 62 new imported Covid-19 cases were reported across the mainland.

Monday also saw 15,355 new asymptomatic cases on the Chinese mainland, including 15,239 local ones and 116 imported ones, according to the commission.

Among the asymptomatic cases, 13,086 were reported in Shanghai and 1,680 in Jilin.