Shanghai citizens must take at least one nucleic acid test every week through the end of July, in a new measure to "consolidate the city's COVID-19 prevention fruits," the city government announced on Saturday.

Otherwise their health code will turn yellow, preventing them from taking public transport or entering any public areas, Xia Kejia, the official taking charge of the city's PCR screening, told the city's COVID-19 press briefing.

The free polymerase chain reaction (PCR) service at the city's various regular testing sites will thus be extended to July 31, said Xia.