Shanghai resumed part of its public transportation services on Sunday after more than one month of suspension since early April.

Four metro lines — Line 3, 6, 10 and 16 — and 273 bus routes that form a network covering the urban areas and provide access to the city's airports, railway stations, major hospitals and commercial districts have resumed operations.

Many passengers took Line 10, which stops at the Shanghai Hongqiao Airport and Shanghai Hongqiao Railway, but the subway carriages were not crowded, local media reported.

Eight bus routes linking Shanghai Pudong International Airport and areas west of the Huangpu River as well as 19 bus routes, of which their terminals are the city's railway stations, resumed operations at around 6 am on Sunday.

Zhao Dandan, deputy director of the Shanghai Health Commission, said that beginning on June 1, if a residential community or a village reports no new COVID-19 infections over the past two weeks, it will be classified as a low-risk zone.

Shanghai registered 52 local COVID-19 confirmed cases and 570 asymptomatic infections on Saturday. All the infections were found inside quarantine and locked down populations, according to the Shanghai Health Commission.

As of Saturday, the number of residents in locked down zones in the city with a population of 25 million has further shrunk to 510,000.