Aerial photo shows people playing roller-skating at a playground beside the Liming Lake in Daqing, northeast China's Heilongjiang Province, Sept. 7, 2021. China's Daqing Oilfield announced on Aug. 25 the discovery of a major shale oil field with predicted geological reserves of about 1.27 billion tonnes. Discovered in 1959, Daqing Oilfield has made a significant contribution to China's modern petroleum industry system. It also steps up efforts to improve its ecological environment in recent years. (Xinhua/Wang Jianwei)
