"I hoped people would learn about volunteers by publishing the video online," he said.

Tsui immediately signed up as a volunteer when a local property management company started recruiting helpers after the outbreak in early March. His community, which includes 12 residential buildings, has a population of more than 3,000.

In addition to delivery of food and other daily necessities door-to-door, Tsui and other volunteers help local residents buy medicine and assist pregnant women and the elderly who live alone to connect with doctors as needed.