China ordered its largest lockdown in two years Monday after a growing outbreak of COVID-19 erupted in Shanghai, forcing 10 million people back into their homes despite decreasing cases in the rest of the world.

Shanghai’s lockdown will occur in two phases after 3,500 new cases were confirmed Sunday. In the first phase, Shanghai’s financial district and neighboring areas will be locked down from Monday to Friday. In the second phase, Shanghai’s downtown will be locked down for five days starting Friday.