全长约６３００公里的中国最大河流长江变得黄浊起来。这是因为对森林的乱砍滥伐和耕地化导致水土流失严重。为防止出现“黄河化”现象，禁止采伐天然林、退耕还林、退耕还草的工作在四川省等２０多个省市自治区展开。金沙江流经四川省和西藏自治区境内（称为长江上游），水量 The Yangtze River, China’s largest river, about 6,300 kilometers in length, has become turbid. This is because erosion and deforestation of forests lead to serious soil erosion. In order to prevent the “Yellow Riverization” phenomenon, it is forbidden to cut down natural forests, return the grain plots to forestry and work on returning farmland to grassland to more than 20 provinces and autonomous regions in Sichuan Province. The Jinsha River flows through the territory of Sichuan Province and Tibet Autonomous Region (called the upper reaches of the Yangtze River) and the amount of water