When Chinese authorities made the decision, it went into effect immediately.
In an effort to contain the coronavirus epidemic, entire cities, including Wuhan, the epicentre of the contagion, went into lockdown in the central Chinese province of Hubei in late January.
Nearly 60 million people were largely confined to their cities by central government decree, with school and work cancelled across the country.
That effort appeared to start paying off last week as China reported fewer than 200 new cases of fresh infection each day, down from last month when there were several days with more than 3000 new cases.
With the coronavirus already detected in more than 90 countries and caseloads climbing more quickly abroad than within China, governments are scrambling to find the best methods to keep the contagion at bay.
But how much can other countries borrow from China's coronavirus playbook, given the toll the limits take on personal freedom and economic activity?
So far, China is the only country that has dealt with a large-scale outbreak and brought surging case numbers under control, at least for now.
"China's bold approach to contain the rapid spread of this new respiratory pathogen has changed the course of a rapidly escalating and deadly epidemic," the WHO wrote in a report on its joint mission to China last month.
"These are the only measures that are currently proven to interrupt or minimise transmission chains in humans."
But the WHO has also stressed that there is no one-size-fits-all approach. Health specialists said that some parts of China's model, involving the lockdown, or "cordon sanitaire", of epicentres and what WHO calls "extreme social distancing" measures could be applied elsewhere.
"In Wuhan, the cordon sanitaire slowed the process, and [infections] did not emerge at the same strong pace around the country, so it was possible to bring support - sending doctors and supplies from other parts of the country - to the city, which had to face a huge outbreak, while there were much better conditions in other cities," said Antoine Flahault, director of the Institute of Global Health at the University of Geneva.
"It is an experience that we can now learn from on a very large scale."
A version of this model has already been applied in Italy, where a large portion of the country's northern region, including Milan and Venice, went into lockdown on Sunday.
The restrictions affect some 16 million people, or about a quarter of the population, in a country that has roughly 4600 confirmed cases of Covid-19, the disease caused by the coronavirus. Prime Minister Giuseppe Conte said there would be some exceptions for travel for "work-related reasons, emergencies or health reasons".
The move marked an expansion of an earlier, smaller-scale lockdown of 11 northern Italian cities at the centre of the national outbreak.
Two other hard-hit countries - Iran and South Korea - have not implemented such stringent measures, despite having numerous cases of local transmission of the disease. The South Korean government has declared three "special care zones" around the outbreak epicentres, promising more resources and warning people against travelling there.
The country has relied largely on a rigorous testing programme to control the spread, with more than 7000 cases in total. In Iran, the government has imposed some restrictions on travel between major cities, closed schools and called on Iranians to avoid public places, according to media reports.
Adam Kamradt-Scott, an associate professor at the University of Sydney who specialises in global health security, said governments should be trying to stop transmission, but "it's important to make sure that the measures are proportionate to the nature of the outbreak".
"It's a spectrum - you can implement very severe measures and stop transmission fairly rapidly, but that might also cause significant economic damage," Kamradt-Scott said.
"Governments could follow China's example quite closely, but the main concern that has arisen around China's responses has been with regards to the implications for human rights, and there's quite a difference in how countries approach these issues."
Some countries like the United States and Canada have a bill of rights which afford their citizens certain guarantees.
"Some countries have taken more limited steps such as banning big gatherings, cancelling school classes, and adding international travel restrictions. But working out what to do next will depend on economic and governance considerations, as well as how big a burden each health system can handle," according to Hannah Clapham, an assistant professor at the National University of Singapore's Saw Swee Hock School of Public Health.
"The big phrase being used there is 'flattening the curve'. That's the point where different countries will be thinking 'what can we handle and how do we put in place different interventions to make sure that things maintain below the level that we can handle' - mainly that's about ICU beds," Clapham said.
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Different measures for social distancing, including working from home, changing the hours of public transport, and cancelling large gatherings can help to adjust this peak, whereas a lockdown may only work when there is a clear epicentre.
Flahault said these kinds of measures could buy countries time as they prepared for cases around the country.
"It's better to have a longer period with hundreds of people coming to your hospitals rather than a shorter period with thousands because of the quality of the health care, which can be absorbed. This wave cannot be maintained if the wave is a tsunami," he said.
If a mass lockdown is enforced, the burden falls heaviest on those behind the containment walls, bringing its own problems, according to Yanzhong Huang, senior fellow for global health at the US-based Council on Foreign Relations.
"[With] the lockdown of Wuhan, many of those infected patients were unable to get timely treatment, unable to be hospitalised, and that contributed to the rapid spread of the virus, probably, in the city and in Hubei province," Huang said, noting it could also have led to a higher mortality rate.
"Much of the Chinese experience is not replicable in other countries, given the size and the totalist state's ability to mobilise the bureaucracy, mobilise the society to tackle a common challenge.
"You have all those legal and logistical challenges in a democracy like the United States, even if you want to lock down the city."
Other densely populated cities such as Hong Kong and Singapore offer alternatives. Both places reported cases early in the epidemic and had community transmission of the disease, but both have kept their case numbers low so far through proactive testing, travel restrictions, home quarantine and rigorous contact tracking of confirmed cases.
For countries that only have a small number of infections, or only imported cases, finding ways to stay ahead of the virus is vital. That's the situation in Lebanon, which, like many countries has just a few cases, but also operates with a health system that could be overburdened by a sharp outbreak.
Twenty-two cases have been found, so far, including at least two who entered the country and were moving around freely, despite Lebanon's airport screenings, travel restrictions, and home quarantine for those from high-risk countries, according to Hassan Zaraket, assistant director at the Centre for Infectious Diseases Research at the American University of Beirut.
"Now we have a window of one to two weeks to know [from] these two cases how many people might develop symptoms, as we have more of these cases the problem would become more challenging," he said.
Zaraket said those concerns were compounded by ongoing protests and a financial crisis, with capital controls that make importing medical supplies challenging.
"If anyone loses their grip, if people start becoming less compliant or the government stops [case-detection] measures, then I would think there's a likelihood for a sustained community spread," he said.
"I hope we don't have to deal with a large-scale pandemic."
-South China Morning Post