Northwest China's Shaanxi province is facing another outbreak of Covid-19.
Its capital Xi'an, a city of 13 million, is on high alert.
Authorities have been on a campaign to track, test and quarantine potential cases.
Over the past few weeks, Xi'an Metro has ramped up disinfection routines, despite the drop in passengers.
The inspection machines, the self-service ticketing machines and the turnstiles are disinfected every hour.
The escalator handrails, toilet doorknobs and elevators are disinfected every four hours.
And the one-time ticket cards are recollected and disinfected every day.
Xi'an Metro says it's also implementing passenger flow control, as necessary.
Several districts and counties have already begun a second round of COVID testing.
Some healthcare workers say it's been tough, but the sense of community is strong.
After getting tested, they thank us. Some people have even given us milk tea. We feel very touched.
检测完后，他们会感谢我们 。有些人甚至还会送我们奶茶 。我们很感动 。
At this community on Lianhu Road, residents say testing procedures have been orderly.
Social distancing is maintained, and face masks are kept on.
They say it's with mutual understanding and cooperation between health and community workers that the outbreak will come to an end.