Aerial photo taken on April 10, 2019 shows the Zhaozhuangzi Village of Anxin County in Xiongan New Area, north China's Hebei Province. Restoration work has started in Baiyangdian Lake, northern China's largest freshwater body. High-pollution and energy-intensive production has been tackled. As a result, water quality has improved remarkably. (Xinhua/Mu Yu)