The central Chinese city of Wuhan conducted more than 6.5 million novel coronavirus tests in 9 days, according to state media, a drastic move by authorities to prevent a second wave of infections in the original epicentre of the global pandemic.

Wuhan’s ambitious citywide nucleic acid testing drive came after six new cases emerged in a residential community earlier this month — the first time local infections were reported following the city’s emergence from its months-long lockdown in April.

From May 15 to May 23, swab test samples were collected from more than nine million residents, China’s state broadcaster CCTV reported, accounting for more than 80% of the city’s total population of 11 million.