To improve the water quality of the Victoria Harbour, the Harbour Area Treatment Scheme (HATS) formerly known as Strategic Sewage Disposal Scheme was committed in late eighties to be implemented in stages to provide treatment for the sewage collected from the urban areas on both sides of the Harbour. Stage 2 was implemented in two phases, Stage 2A and Stage 2B. Stage 2A was commissioned in December 2015 providing treatment to the remaining 25% of sewage generated from the northern and southwestern sides of the Hong Kong lsland. In addition, disinfection facility was installed to improve the quality of the effluent and hence harbour waters, making it possible to re-open the Tsuen Wan beaches.