With the cluster at Bukit Merah View Market and Food Centre growing (Bukit Merah View market to stay shut as cluster grows to 39, June 17), I wish to highlight several safety concerns in markets and non-air-conditioned food centres.

Due to the hot and stuffy environment, compliance with mask wearing is generally poor. Many vendors and food stall owners can be seen with their masks not fully covering their nose and/or mouth.

When they take "mask breaks", undetected Covid-19 carriers risk spreading the coronavirus.

Smoking in markets and food centres is also rampant all over Singapore, even in the toilets. I have encountered this in Bukit Panjang, Bukit Timah and Woodlands.

Professor Leo Yee Sin from the National Centre for Infectious Diseases notes that it is possible to get infected by Covid-19 if someone is near smokers carrying the virus while they puff away with their masks off.

What is most worrying is that people who display Covid-19 symptoms like fever, cough, running nose and loss of smell still do not see a doctor soon enough, and do not isolate themselves to prevent community transmission.

There are also commuters who cough or sniffle on buses. Though masked, they may still pose a risk to other commuters if they carry the coronavirus, as no mask is 100 per cent protective. Research has also shown that the virus can enter the body through the eyes.

The enclosed space and proximity among commuters on buses put everyone in jeopardy. Furthermore, the increased transmissibility of the Delta variant currently circulating here compounds the problem.

To keep Singapore safe, I propose the following:

• Add stall vendors and helpers at all markets and food centres to the rostered routine testing regime;

• Deploy safe distancing ambassadors on buses to ensure proper mask wearing;

• Issue mandatory swab orders to anyone found coughing, sniffling or blowing their nose on buses and elsewhere (if they have not just been swabbed).

Liu I-Chun