Skyscraper window cleaners in Saigon hard at work during the busy year-end season earn VND1 million ($43.35) a day, double the norm. 

At an apartment block in Phuoc Long B Ward of Thu Duc City, a group of workers are tasked with cleaning the windows of more than 600 apartments. Standing on the roof of the 17-storey building, Cai Bao Thanh in a black T-shirt is about to tie the rope to some pillars to swing downstairs and start work. The ropes can bear a load of 2,000 kilograms.

"This is a very important job that requires high concentration. Only a small mistake could see you pay a heavy price," said the 26-year-old man. 

The year end is the busiest time for window cleaners as many high-rise buildings and apartments in HCMC enjoy a spruce up in celebration of Tet, Vietnam's biggest and most important holiday that peaks on Feb. 12 this year.

Thanh has been in the profession for six years.

"For window cleaners like me, the year end is the busiest season. During this peak time, I could earn VND1 million a day while in off-peak months, I only work 10 days a month," he said. 

Cleaners use safety belts buckled at the waist and fitted with straps attached to a pair of anchor bolts fixed at the top of the building.

Workers have to buy their own cleaning gear, which typically costs around VND1 million.

Nguyen Van Huy swings down the rope to start work.

"A newbie starts out with low buildings. As he becomes more experienced, he will get to do larger and higher buildings. However, many people quit after a short time because they cannot stand the risky job," the 35-year-old said. 

A landlord takes a photo of the cleaner hovering in front of her living room window. 

Nearly half an hour in the air, Huy continuously wipes away sweat.

"The ideal weather to clean windows is when it’s cool and not windy. When it’s sunny, it make us easily lose strength while if it’s windy, it’s very nerve-wracking," he added.

Le Hoai Phong, 42, cleans the bedroom windows of one apartment.

Phong said they are most afraid to work at newly built buildings, the windows of which are marked with lime and dust.

At around noon, Phong finishes his morning shift and waits for his colleagues to come down for lunch and rest.

During more than 10 years in the job, his worst fear is strong winds that cause him to sway in the air.

"Only when our feet touch the ground do we feel safe," he said.

In the afternoon, the group cleans the windows of the remaining apartments. It usually takes from a week to half a month to complete the work depending on the area and height.

"Window cleaners are aware of the potential dangers involved. We bet our life on the job," Thanh said.

Many amazed Saigonese have given them the nickname "Spidermen."

After lunch, they rest for an hour beside the exit on the apartment terrace.