Singapore has weathered Covid-19 for over half a year, and the battle against the virus is increasingly becoming a mental one.

Psychological fatigue and a false sense of security are behind the crowds gathering at beaches, restaurants and shops, say experts.

This is particularly since community cases remain low despite many businesses opening again.

After months of facing the strain of Covid-19, it is inevitable that individuals start to let down their guard, become complacent, or simply frustrated, said Professor Teo Yik Ying, dean of the National University of Singapore's Saw Swee Hock School of Public Health.

And this can lead to careless behaviour.

This was clearly the case on Sunday, when crowds gathered to watch Red Lions parachuters land at a grass patch next to Sengkang General Hospital, and some people ended up arguing with safe distancing ambassadors trying desperately to maintain the rules.

While most Singaporeans are rule-abiding, there are always those who push the boundaries and take unnecessary risks, noted sociologist Pauline Straughan. This could be due to either ignorance, or - when enforcement officers are not around - "simply because they can".

She added: "I think in the beginning, most will be cautious when they venture out.

"However, when this is normalised and especially when nothing happens when we resume social activities, many may tend to let their guard down. So what we need is constant reminders, and rule enforcement to guard the boundaries."

Prof Teo said to stem such behaviour, public education is paramount, which means constant reminders of what is risky and what is not.

"By constantly being informed about the situation locally, this can help individuals to decide which activities are now permitted because the necessary precautions are in place to make it safer, which activities remain at a higher risk and therefore controlled, and which activities are strictly disallowed because the possibility of community transmissions in these settings is extremely high."

Equally important is cultivating a sense of restraint and control, he added.

"Forbearance, by individuals as well as by the enforcers of rules and regulations, is important," he said. "If one does forget to wear a mask or abide by safe distancing regulations genuinely, it's important that the public and enforcers do not be too quick to castigate... But of course, if one is clearly recalcitrant, then penalties and sanctions ought to apply."

Added Professor Dale Fisher, a senior consultant at the division of infectious diseases at National University Hospital: "We need to learn to live with this virus. This requires community behaviour to stay in line with all the guidelines and rules."

Another reason for the spike in cases in several countries is the lifting of lockdowns prematurely.

Indeed, the World Health Organisation has stressed that countries should ease restrictions only when they have put in place adequate systems to track, trace and isolate all cases in the country.

This has been a misstep in some countries. In the United States, for instance, in two-thirds of states, infections were rising when governors started to ease lockdowns, according to a report in The Economist.

Singapore appears to have avoided this with its slow and careful entry into the new normal, carried out in phases and with the riskiest activities still on hold for now.

"The pace of reopening in Singapore is quite reasonable, when you consider what has happened in countries that reopened too soon and too fast," said Associate Professor Alex Cook, vice-dean of research at the Saw Swee Hock School of Public Health.

"This is especially so when you consider that we still have large numbers of cases being identified in the dorms, and the risk of spillover."

Still, a cluster could happen any time and anywhere. The community cluster at the Bukit Panjang integrated transport hub, that was uncovered last Friday, is a case in point.

To protect themselves, Singaporeans should be prudent and maintain a limited number of contacts during this period, Prof Teo said.

He added: "However, if one of your contacts is a social butterfly and continues to maintain a very diverse social circle, then clearly your risk is still amplified.

"This is why we keep emphasising that the success of keeping Covid-19 at bay depends on everyone's cooperation, to keep to the spirit of the regulations around social activities in order to protect the community."

Just because an individual can meet up with four other friends during this period does not mean he should take advantage of this and meet up with many different groups of four others, he stressed. "This is a privilege that can just as easily be rescinded if the Covid-19 situation in the community flares up again."

Ms Lydia Lim, 24, who works in tech supply, has taken this advice to heart. She has been limiting her social interactions to two to three times each week, each time keeping to around two to three people.

"I think the circuit breaker has helped me to rethink my social interactions and prioritise the gatherings which I attend - and I think this will definitely change the way I spend my time in future," she said.

• Additional reporting by Cheryl Tan