Looking up, they discovered that the blocks were part of the building wall which broke off from the 16th floor!
The big break likely took place in the wee hours of morning.
According to one resident, he had sent his daughter home at around 2am and didn’t find any debris on the ground, but to his horror, the concrete blocks were there at 7am when he went downstairs.
The debris spans the area roughly the size of a typical rectangular dining table.
No casualties have been reported.
They are worried that the incident might re-occur and the next time, someone might get hurt.
They want the HDB and town council to conduct inspections on the buildings to avoid a repeat.
Police and town council cleaners have cleared the debris and the area has been blocked off temporarily.
The HDB blocks at Choa Chu Kang Avenue are around 18 years old, according to residents.