BEIJING (BLOOMBERG) - As the first major country to emerge from coronavirus lockdowns, China is focused on avoiding a devastating second wave of infections as it returns to a semblance of pre-pandemic life.

Distanced school desks, compulsory face masks and tracking apps are being deployed from the financial hub of Shanghai to the frigid northern province of Heilongjiang.

With Chinese experts concluding that the virus cannot be eradicated, government officials are focused on keeping infections to a manageable level to avoid catastrophic surges that overwhelm hospitals.

This balancing act between letting people return to normal life while keeping infections at a low level is one that governments around the world, including the hardest-hit nations like Italy and the United States, will have to try to master.

Even with tools that others don't have - powerful state surveillance and control of people's movements - China doesn't have a full picture, nor any guarantee of success.

"All of which means that as China restarts its economic and social life, there are known unknowns that could viably lead to another outbreak," said Nicholas Thomas, a professor specialising in public health at City University of Hong Kong.

Here are the strategies Chinese cities are trying:

DEALING WITH THE BORDER THREAT

Unfettered global travel will likely no longer be possible in a post-virus world as countries fear imported infections setting off new waves. Almost all foreigners are banned from entering China while citizens coming back from overseas have to spend at least two weeks in isolation.

The most strictly-governed cities, like Beijing, are enforcing an additional seven days of home confinement after that. Anyone isolating at home in the capital city can trigger an alarm just by opening their front door while neighbours are encouraged to report people leaving their homes.

The extreme restrictions have gotten tighter even though there have been barely any new local cases in weeks, due in part to the political class that reside there.

"Beijing is the capital, many government leaders live there and they have to consider the political impact and social stability concerns," Huang Yanzhong, director of the Centre for Global Health Studies at New Jersey's Seton Hall University.

Other Chinese areas with the most draconian limits on travel include border provinces like Heilongjiang, which has seen a wave of infections from people crossing over its land border with Russia. It now requires 35 days of quarantine for such travellers, restricting import-export businesses in the region and pointing to a likely global future where economies dependent on border flows contract.

In financial hub Shanghai, hardly any restrictions are imposed on domestic travellers likely due to the need to remain open to investment and talent.

A Bloomberg journalist travelling from epicentre Hubei province to Shanghai didn't encounter any particular restrictions, quarantine or even a requirement for testing once in the city.

Shanghai's approach will likely be watched closely by authorities in other financial centres such as New York and Tokyo, cities whose dynamism depend on open domestic travel.

MASS TESTING

While many countries are still struggling to test everyone who appears sick, Chinese cities are now trying to preemptively test those returning to work.

In Hubei and Guangzhou provinces, companies are asking returning workers to take virus tests. In Shanghai, voluntary testing has been rolled out city-wide and companies and individuals can book tests at hospitals and clinics.

Clinics, infectious disease specialists and the local Center for Diseases Control are coordinated to identify, diagnose and isolate infections early, followed by swift contract tracing and quarantine to prevent community spread, according to Zhang Wenhong, the director of infectious diseases department at Shanghai Huashan Hospital.

"In Shanghai there's thousands of CDC people and doctors hunting down these patients and isolating their close contacts," Zhang said. "That's critical for swift response in the prevention and control system."

TRACKING APPS

In a move likely impossible in Western democracies due to privacy concerns, China is combining the powers of its surveillance apparatus and its giant internet companies to keep tabs on who is vulnerable to infection.

Tracking and health monitoring functions built into smartphone apps from Alibaba Group Holding Ltd. and Tencent Holdings Ltd., China's biggest companies, draw on data from government departments, phone carriers, locations and transactions to paint a detailed picture of each individual's risk level.

The end result is that millions of people have to show their red, yellow or green colour codes before being allowed into hotels, restaurants, shops, subways and residential compounds.

The codes are updated frequently and a green code - which gives freedom of movement - can be easily lost. Just visiting a shopping mall that an infected person also went to can mean one's code changes to yellow, forcing mandatory home isolation.

GRADUAL REOPENING

While there has been an easing in restrictions, China has been careful to do so in stages. Many cities still don't allow cinemas, theatres or bars to reopen, while the notorious traffic jams of Beijing and Shanghai have intensified as many shun the close confines of urban transit.

Face masks, already a common sight in China, have gone from optional precautions to mandatory in workplaces and public transport.

Heilongjiang shows how quickly and unexpectedly new waves of infection can surge. A student who returned from the US in March spent two weeks in quarantine and tested negative, and then likely still infected dozens others. Two hospitals had to be shut for disinfection, the city of Harbin delayed re-opening schools and housing compounds were locked down.

The province also reported more than 370 imported infections since the beginning of April, mostly Chinese nationals who crossed the land border it shares with Russia.

Still, the patchy reopening hasn't yet led to any significant national waves of new infection, giving hope to other countries as they start to plan to scale back their lockdowns.

"Nobody wants to see another spike in cases by rushing the lifting of restrictions too soon," said Takeshi Kasai, the World Health Organisation regional director for the Western Pacific region at a briefing last week.

"Individuals and society needs to be ready for a new way of living."