Every day, Madam Lee Yew Tin lugs bags of garbage a distance of two Olympic swimming pools, a journey she makes at least twice a day.
When the 68-year-old became a cleaner about three years ago, she earned a basic wage of $1,000. Since then, she has had a pay rise of... Nothing.
She works nine hours a day, five days a week, sweeping corridors and clearing rubbish.
"It's very tiring and my legs hurt all the time now," she says in Mandarin, declining to name her employer or the place at which she works, saying it might affect her job.
Madam Lee is among low-wage workers affected by a trend in which companies, wanting to save costs, outsource services to the cheapest service provider. However, those successful tenderers often are able to win the service contract only because they cut back on wage rises given previously.
SUPERVISORS HAVE TO WORK HARD TOO
As supervisors we have to be hands-on as well. We have to do the work to show we know it is tiring, that we don't just 'see' only.
Ms Joey Wee
This is because the PWM requires only the minimum pay tied to each tier of the model. Hence, with a typical cleaning contract lasting three years, the winning bidder can "reset" a worker's wages to minimum.
Only 42 per cent of companies with outsourced workers gave their low-wage workers a pay rise of at least $60 last year, as recommended by the National Wages Council. Its guidelines apply to workers earning up to $1,100 a month in basic wages.
Madam Lee, who has diabetes, does not get any medical benefits from her company.
She will also lose any additional days of leave she accumulates through her service every time her contract is renewed.
She does not want to burden her three children, who are in their 30s and 40s, with her upkeep, but fears she may have to resort to this by the end of the year.
"The work is too hard for this kind of money," she says.
Her story is a far cry from that of Ms Joey Wee, a relative newcomer to the industry, yet already on the other end of the spectrum.
Ms Wee, 40, joined cleaning firm ISS last October as a supervisor heading a team of 20 cleaners at a hospital. But despite her leadership role, the job requires her to get her hands dirty from time to time.
She left her linen attendant job for the cleaning industry to get a $500 pay hike in monthly wages.
She earns $1,800 a month at ISS, up from $1,300 when she led a team that distributed linen at another hospital.
Under PWM, a cleaning supervisor earns at least $1,600 in basic monthly wages. If Ms Wee reaches the level of a cleaning executive, she could earn at least $2,000 a month.
Ms Wee had no notion of what the PWM was, but the linen distribution industry has no such model in place and she knew greener pastures when she saw them.
Still, the new job has not been without its challenges. She recalls her hesitation at cleaning her first bloodstain. "You don't know where the blood is from. It could be from someone infected."
Once, she spent two hours scrubbing a mysterious yellow stain on the floor from a chemical spill.
Making her role a little easier are the tools of the trade, as ISS increases automation for its 4,000- plus cleaners.
Machinery they are trained to use includes burnishing machines, with which they polish the floor, and the iMop, a recent addition which does the job in a third of the time it would take with a regular mop.
Even so, Ms Wee says the job is so tough it sometimes brings workers in her charge to tears.
"Sometimes the staff get emotional, saying there are too many things to do. I have to talk to them, slowly calm them down."
She adds: "As supervisors we have to be hands-on as well. We have to do the work to show we know it is tiring, that we don't just 'see' only."