Nanguang Expressway is an important north-south passage connecting the west of Shenzhen to Hong Kong and the Pearl River Delta. It was opened to traffic in 2008. The main line is 30 kilometers long and passes through the Xili Reservoir water source protection area. The project draws on foreign road environmental protection practices and is designed within the water source protection area. Special sewage pipelines have been built to implement key protection of water sources.