The megacity, with a population of 13 million, imposed closed-off management for communities and villages last Thursday. Residents have also been asked not to leave the city unless necessary.
Long-distance passenger transport lines have been suspended, except for freight vehicles transporting epidemic prevention materials and daily necessities.
Taxis and drivers working for online ride-hailing platforms may not enter medium or high-risk areas or travel outside the city.
Aerial photo shows a closed toll station of an expressway in Xi'an, northwest China's Shaanxi Province, Dec. 25, 2021. (Xinhua/Tao Ming)
"For Xi'an, intensified control and screening measures are urgent to block the virus as soon as possible," said Zhang Boli, an academician of the Chinese Academy of Engineering.
"I estimate the transmission will be cut off in mid-January and the outbreak can be completely put under control in late January. It is very possible," he said in a recent media interview.