A man takes a PCR test at a testing site in Shanghai's downtown Xuhui District.

Shanghai extended free polymerase chain reaction (PCR) testing service for local residents to the end of November, local authorities announced on Tuesday.

Residents and tourists in Shanghai can find the nearest testing sites easily on the Suishenban app, Shanghai's e-governance platform.

Foreigners can use the information in the following link to locate a testing site (https://www.shine.cn/covid19/2209210670/).

Citizens are required to do a PCR test at least once per week, otherwise, their health codes will turn yellow. Their health codes will return to green within 24 hours after they take a test if the result is negative.

And if people want to go to public places or use public transportation, a negative report within 72 hours or proof of testing within 24 hours is needed.

The free PCR test policy will be adjusted based on the COVID-19 situation, said health authorities.