Such QR codes have been posted at the entrances to residential communities, companies and other public places in Hangzhou. Those who want to enter public spaces or take public transport vehicles are required to show their green health codes. Those who don't have smartphones, especially the elderly and children, can pass with valid paper documents.

As of Feb 17, the health QR code system had been applied in all 11 cities in Zhejiang.

Based on the province's pilot practice, the General Office of the State Council developed a national health code system with Ant Financial and promoted it nationwide on Feb 29.

The code serves as a regional "traffic permit" to ensure orderly population flow during the COVID-19 outbreak.