bejing china locked down the western city of xian on thursday to stamp out a persistent covid outbreak its biggest such move since the pandemic started in wuhan underscoring how the countrys zerotolerance approach hasnt allowed it to move on since the virus emerged nearly two years ago the 13 million residents of xian were told to remain in their homes and to designate one person to go out every other day for necessities triggering fights over access to food nonessential travel out of the city was banned this came after a second round of mass testing pinpointed 127 covid infections scattered across 14 districts making containment of the virus grave and complicated the official xinhua news agency reported the rising number of cases underscores the challenge china faces at a time of increased holiday travel and preparation for the winter olympic games which will feature an influx of athletes and their entourages in february the vast majority of the infections stem from the delta variant which spread through most of the world in the summer and fall the country is girding for the more infectious omicron strain which has been shown to evade immunity from vaccination or previous infectionchinese vice premier sun chunlan urged swift measures to curb the spread of infections the report said sun whose membership in the 25person politburo makes her one of chinas mostsenior officials also stressed the importance of tightening restrictions on the movement of people to prevent large gatherings in key areas according to xinhuaprotracted battlethe lockdown of xian is the latest escalation in chinas efforts to extinguish local transmission of the delta variant as it becomes the only country in the world still bent on eliminating the virus and bringing cases to zero to prevent the infections in xian from flowing into other areas the city cancelled all domestic flights on thursday local media reported in the paper throughout the pandemic officials have been able to stamp out outbreaks within about a month through mass testing aggressive contacttracing and targeted lockdowns yet as the viruss new strains become more infectious increasingly disruptive measures have been needed to contain outbreaks putting pressure on the worlds second largest economy its been more than two months since there were no new local cases of covid in chinastill burningwhile local authorities have in the past used targeted lockdowns to slow outbreaks in smaller places in china no major city has been put under mass restrictions since wuhan in early 2020 it has a similar population size as xian officials in beijing on thursday acknowledged that there will inevitably be covid infections at the winter olympic games which are set to begin in early february they urged all participants to get booster shots to better protect against the virus especially those caused by the immunityevading omicron variantthe outbreak in the city the capital of many ancient chinese dynasties thats known for its terracotta warriors traced its roots to a flight from pakistan a cleaner at a quarantine