Sinkhole on Tanjong Katong Road traced to sewage shaft failure at PUB worksite

A sinkhole that formed on Tanjong Katong Road South on 26 July 2025, engulfing a car, has been linked to a structural failure at a national water agency (PUB) sewer construction site.

PUB confirmed on 27 July that a concrete caisson ring — part of a 16-metre-deep sewage shaft — had failed at about 5.50pm, triggering the collapse of the adjacent road and the formation of the sinkhole.

Quick rescue by workers

The incident could have turned tragic, but nearby construction workers from Ohin Construction acted swiftly.

The driver, a woman, managed to climb partially out of her car before being pulled to safety by workers using a nylon rope.

Site foreman Pitchai Udaiyappan Subbiah, 46, said he and three colleagues rushed to the scene after hearing a loud noise. “There was one car, and one woman was inside. I thought, somebody fell inside — I want to help,” he recounted.

Subbiah stopped one of his workers from descending into the hole, instructing them instead to throw a rope. Within five minutes, they successfully pulled the woman out. He added that the sinkhole had not yet filled with water at the time of the rescue.

SCDF and public commend rescue efforts

Initial statements from PUB had credited the Singapore Civil Defence Force (SCDF) for rescuing the driver, but SCDF later acknowledged the workers’ role, commending their “bravery and prompt action”.

The driver was taken conscious to Raffles Hospital for checks. Mountbatten MP Gho Sze Kee said the woman remained under observation for muscular pain but was able to walk.

Cause and immediate response

PUB said the collapsed caisson ring had been part of works to link three existing sewer lines beneath Tanjong Katong Road South. Preliminary findings suggest that the ring’s failure caused the sinkhole to open beside the construction shaft.

To stabilise the ground, PUB filled the shaft with material and carried out ground-penetrating radar scans to assess surrounding subsurface conditions.

A safety time-out has been declared across all similar sewer construction projects to review safety standards and structural integrity measures. PUB is working with the Land Transport Authority and the Building and Construction Authority on investigations and repairs.

Road closures and repair work

Following the incident, water was pumped from the sinkhole between 9.45am and 1.20pm on 27 July. The car was hoisted out at about 2pm.

PUB then filled the cavity with liquefied stabilised soil to prevent further collapse, after which road reinstatement works began.

Tanjong Katong Road South remains closed between Mountbatten Road and East Coast Parkway until repairs are complete. PUB has advised motorists to plan alternative routes during weekday peak hours.

Water supply to 18 nearby households was disrupted for several hours due to ground movement damaging nearby mains. The affected pipes were isolated, and water service was restored by 2.30am on 27 July. PUB said the damaged mains had contributed to water gushing into the sinkhole, as seen in videos shared online.

Public reaction and commendation

Singaporeans have praised the construction workers for their quick thinking and courage. Videos showed them rescuing the woman and later erecting barricades to prevent further danger.

Subbiah recalled that after the rescue, the woman said her phone and identification card were still in the submerged car. He lent her his phone to call her daughter. “We saved a life… whatever happens, that is all that matters,” he said.

PUB has apologised for the disruption and promised to update the public on repair progress and the road reopening timeline.