Fearing that the conditions of his living quarters could increase his risk of coronavirus infection, Mr Mohan, 34, volunteered to help clean up the S11 Dormitory @ Punggol which was suddenly locked down on April 5.

At that time, S11 had 63 confirmed cases of Covid-19 and was designated as an isolation area by the Ministry of Health. As at yesterday, the dormitory located at Seletar North Link had 2,211 cases, making it Singapore's biggest cluster.

Back then, workers had described the dorm with 13,000 residents as crowded, unsanitary, infested with cockroaches and with overflowing toilets.

On the second and third day of S11's lockdown, Mr Mohan said he had helped to wash the toilets on the floor where he stays.

As there were not enough cleaners, he had also helped to clear the trash, and volunteered to collect food packs dropped off by caterers at the gate of the dorm for his roommates.

On the fourth day, he started to feel unwell.

"I felt feverish, but when I checked my temperature, it was 37.4 deg C. I also had a headache," said the Indian national, who wanted to give only his first name.

Mr Mohan, who was sharing a room with nine others, did not leave his room for the next two days, except to go to the toilet.

On April 11, his temperature rose to 38.6 deg C. He went to see a doctor stationed at the dorm that same day. "After that I was not allowed to return to my room," said Mr Mohan.

Together with about 10 other people, he was taken in a bus to Cherryloft Resorts at Jalan Loyang Besar, now a quarantine facility. There, he went through more tests.

In the following days, more symptoms started to appear.

"My temperature was fluctuating every day and I started to cough. I also had chest pain and felt breathless," said Mr Mohan.

"A few days later, a doctor told me I tested positive (for Covid-19). I was very scared. I froze when I heard the news. The doctor said I would be taken to Tan Tock Seng Hospital in an ambulance."

Mr Mohan, who has a two-year-old daughter, decided he would not tell his wife, who is seven months pregnant, about the test result.

"I didn't tell my wife I have Covid-19. When I told her I had fever, she was already crying non-stop. I didn't want her to worry, but I was very scared and I wonder when will I recover," said Mr Mohan.

Speaking to The Straits Times over the phone from his hospital bed yesterday, Mr Mohan who worked at a construction site in Woodlands, said he was so fearful of getting the virus that he stopped hanging out with his friends on his day offs even before the lockdown kicked in.

"I stopped going out in March. I worked on Saturdays and I spent Sundays sleeping in the dormitory. Only on March 8, I went to Little India to buy some vegetables. It was a short trip and I avoided having any physical contact with anyone."

Mr Mohan said he still does not know who had passed the virus to him.

"I stay in the blue zone in the dormitory. At first, only people in the red zone got it. Now, four of my roommates have tested positive," he said.

Related Story Coronavirus cases in Singapore: What we know so far

He added that he is now feeling better, and no longer has pains and aches. He had a swab test done yesterday, and was told that he can be discharged if the result is negative.

Patients can be discharged when they attain negative Covid-19 swab test results on two consecutive days.

"I don't know where they will send me to. I was told to go home. My home is S11," said Mr Mohan, who came to Singapore to work as a construction worker in 2011.

"I know there are a few thousand cases there already. But I am not afraid to go back there. I think my room is already empty. Everyone has already been sent to other places."