Authorities in China’s Wuhan city on Tuesday said that they would test its entire population for Covid-19 after it confirmed the first domestic cases of the Delta variant, Reuters reported.

Wuhan is the city where the novel coronavirus was first reported in late 2019. On Monday, authorities confirmed eight new Covid-19 cases in the city, The Guardian reported. These are the first coronavirus cases in Wuhan since mid-May 2020. Out of these, three cases were of the Delta variant, according to Reuters.

The Delta variant is more than two times as transmissible as the original strains that were circulating at the start of the pandemic, according to the United States’ Centers for Disease Control and Prevention.

“To ensure that everyone in the city is safe, city-wide nucleic acid testing will be quickly launched for all people to fully screen out positive results and asymptomatic infections,” Li Tao, a Wuhan official, told reporters.

Li Yang, vice director of Hubei’s provincial disease control centre, said that new cases in Wuhan, along with infections in the nearby cities of Jingzhou and Huanggang were linked to cases found in Huaian city in Jiangsu province.

China reported 61 domestic Covid-19 cases on Tuesday as an outbreak of the Delta variant reached dozens of cities, AFP reported. Several large cities, including Beijing, have now tested millions of residents, while cordoning off residential compounds and placing close contacts under quarantine.

The administration in the eastern city of Yangzhou has become the latest to order residents to stay home after large-scale testing detected 40 new infections over the past day.

China has reported a total of 1,20,837 Covid-19 cases and 5,637 deaths since the beginning of the pandemic.

China has been largely successful in controlling the transmission of the virus within its borders. During the early days of the pandemic, the country managed to limit the transmission of the virus by implementing a stringent lockdown of the entire province of Hubei, in which Wuhan is located. It also conducted extensive testing and contact tracing operations and halted all international travel.

Some experts have said that a late response by China to publicly acknowledge the coronavirus led to an enormous health crisis across the globe, which continues to disrupt normal life.