Ngong Ping is located on Lantau Island, the most important outlaying island of Hong Kong that is home to the famous Hong Kong Internatonal Airport and Asia's longest cable car system. Sewage discharge on Ngong Pong relied on distributed septic tanks and soakway systems that imposed severe limitations on the sewage flow that could be handled. In December 2004, the Environmental Protection Department (EPD) of Hong Kong Government completed the Outlaying Islands Sewarage Master Plan (SMP) Study drawing up a SMP for Lantau Island and other outlying islands. The SMP concluded that the existing treatment and disposal facilities at Ngong Ping had to be upgraded to efficiently handle the increasing sewage generated from both existing and committed developments.