翻译:The Pearl River, a major river system in South China, flows through Guangzhou City and is the third longest river in China after the Yangtze River and the Yellow River. The Pearl River Delta (Delta) is one of the most developed regions in China, covering an area of about 11,000 square kilometers. It is also the world's urban agglomeration in terms of size and population. Nine cities in the Pearl River Delta have a population of more than 57 million. Since China's reform and opening-up in the late 1970s, the Pearl River Delta has become one of the major economic regions and manufacturing centers in China and the world.