SINGAPORE - A study by researchers from three universities here had identified the market and hawker centre in Toa Payoh Lorong 8 as an area significantly more vulnerable to Covid-19, two months before it was identified as a cluster.
The high human traffic in the area and the inability of many people living there to work from home put it at high risk, said the joint study by the Singapore University of Social Sciences (SUSS), National University of Singapore and Singapore University of Technology and Design.
Associate Professor Leong Chan-Hoong from SUSS, who led the study, said the market's location, which served as a conduit for Singaporeans travelling across the island and on the way back from the city, was one reason that made it so popular, and consequently increased the risk of virus transmission.
The area, bounded by Braddell Road and the Central Expressway - two major thoroughfares - is home to vehicle depots, schools and industrial areas, which all contribute to forming a natural bottleneck, adding to the risk.
The composition of the people living in the area was also a contributing factor. Many are elderly or have jobs that do not allow them to work from home.
Prof Leong said this meant that exhortations by the Government for people to stay at home had little effect on the residents there.
He said: "Many of these residents have a different perception of risk than we might.
"They go about their usual activities like buying vegetables at the market, or they have to leave their homes for work."
As for the elderly individuals, they might not have felt they were at risk of catching the virus because they might already be vaccinated, said Prof Leong.
He added that they were also prone to lax observation of safe distancing and proper mask wearing.
The study, from January to June last year, focused on how Covid-19 clusters form. It used data from ez-link cards to study the movement of people to predict which areas had the potential to become staging points for the coronavirus.
The circuit breaker period in particular provided the team with the unexpected but rare opportunity to study the changes in crowd size.
Prof Leong said: "Ez-link card data is extremely useful for us. We are able to analyse the movement of people with data points that provide spatial information at different times of the day."
This allowed the researchers to study the flow of human traffic, particularly during peak hours.
The market and food centre, which has more than 40 cases linked to it, has undergone a three-day closure for deep cleaning.
Mr Saktiandi Supaat, an MP for Toa Payoh GRC, said: "The cleaning and (Covid-19) testing have helped us to stop the spread of the virus, so I am happy with that."
However, he cautioned that Toa Payoh is not alone in facing risks.
"There are many other parts of Singapore where this could happen too," he said.
Meanwhile, the emergence of several Covid-19 clusters in Toa Payoh has been a source of anxiety for those who frequent the neighbourhood.
The biggest cluster is at the bus interchange, which has grown to more than 250 cases.
Technician Paul Tan, 70, lives in Aljunied but uses the Toa Payoh bus interchange during his daily commute to work.
He said: "I only go to my workplace in Yishun. Of course I am worried (about the cluster in Toa Payoh), but I don't have a choice, I still have to go to work. Life goes on. I have to make a living."