Photo taken on Aug. 15, 2019 shows the wetland by Yanhe River in Ansai District of Yan'an, northwest China's Shaanxi Province. The city of Yan'an on the Loess Plateau, where 258 million tonnes of mud and sand were once washed into the Yellow River each year, has seen its landscape improve greatly. Since 1999, local government has returned 718,307 hectares of farmland to forests, increasing the local vegetation coverage rate from 46 percent in 2000 to over 80 percent at present. Data showed that the city reported fewer sand and dust days in recent years, and the annual amount of mud and sand washed into the Yellow River has been slashed by 88 percent to 31 million tonnes. (Xinhua/Tao Ming)