- Drainage Services Department, the Government of the Hong Kong Special Administrative Region
- 168 m below ground level; 163.8 below sea level metre(s)
- Hong Kong SAR, China (Hong Kong)
The deepest urban sewage system installed tunnel measures a depth of 168 metres (551 ft) below ground level and was achieved by Drainage Services Department, the Government of the Hong Kong Special Administrative Region in Harbour Area Treatment Scheme (HATS) Stage 2A Project (Hong Kong), in Hong Kong, China, on 20 June 2019.
The project includes the construction of a 21 km (13 miles) long sewage tunnel with sections which vary from 70 m (229 ft 8 in) to 160 m (524 ft 11 in) below sea level. The construction of this project started from July 2009.