China is racing to build a quarantine center to house 4,000 people in the northern city of Shijiazhuang, the epicenter of the country’s latest outbreak of the coronavirus, which Beijing has largely contained at an enormous cost to its 1.3 billion people.

While much of the world is reporting record numbers of infections, hospitalizations, deaths and disruptions related to the coronavirus, China, the original site of the virus, has avoided a massive resurgence alongside overseeing an economic revival. But it has done so by mandating mass surveillance and periodic lockdowns of entire cities and towns at the first report of new cases.

Despite these efforts, cases of the virus continue to pop up. China has recorded over 100 daily new cases for the past seven days, marking its worst domestic outbreak since March, according to Reuters. At least 11 regions in three Chinese provinces are on lockdown, China’s state-owned Global Times reported Monday.

The government is on edge ahead of the Lunar New Year in mid-February, when millions of people in China typically travel to celebrate with friends and family.

This time last year, reports of a mysterious pneumonia-like virus circulating in Wuhan, China, were raising alarms across Asia. Then on Jan. 23, China ordered a massive, months-long lockdown of 11 million people in Wuhan and the greater Hubei province. In those early days, Chinese workers rushed to build massive quarantine centers and field hospitals alongside implementing mass testing and surveillance measures.

It is a model that China has since replicated across the country over the past year. In Shijiazhuang, the capital of Hebei province, officials are preparing to move entire villages into the quarantine center if needed, Agence France-Presse reported. Close contacts of people confirmed to have the virus will begin to be relocated to the facility when it is completed in the coming days.

Construction began on Jan. 13 after officials put Hebei province’s 11 million residents under lockdown while rolling out mass testing and quarantines. Since early January, the province has reported over 600 cases, the majority of which have been in Shijiazhuang, according to NPR.

Under the current restrictions, anyone who leaves the area must show a negative coronavirus test within the past three days. Close contacts of people who have tested positive are required to quarantine. Last week, around 20,000 people from 12 rural villages were bused to government-run quarantine centers, NPR reported. In three major cities, including Shijiazhuang, people are not allowed to leave their homes.

Hebei province also borders Beijing, which authorities are particularly keen to keep virus-free. As part of the latest measures, only Hebei travelers with proof of work in the capital are allowed to enter.

Chinese authorities have not announced a specific source of the outbreak. However, many of the initial cases were detected in villages around Shijiazhuang’s international airport, NPR reported.