Enlarge / Medical workers take swab samples from residents (L) to be tested for the COVID-19 coronavirus, in a street in Wuhan in China’s central Hubei province on May 15, 2020. – Authorities in the pandemic ground zero of Wuhan have ordered mass COVID-19 testing for all 11 million residents after a new cluster of cases emerged over the weekend. (credit: Getty | STR)

Plans for the gargantuan feat came about earlier this week after officials in Wuhan—the capital city of China’s central Hubei province where the pandemic first began in January—identified a cluster of six new cases over the past weekend. The cluster included an 89-year-old symptomatic man and five asymptomatic cases, all of which lived in the same residential community.

The six cases were the first detection of new infections in more than a month in the hard-hit city—and government officials aren’t taking any chances when it comes to thwarting a dreaded second wave of infections. They quickly announced a plan to test all residents of the city, which number roughly 11 million.