Visitors look at a smart agricultural irrigation system based on the Internet of Things (IoT) technology at an exhibition of high technologies and equipment during the fourth China-Arab States Expo in Yinchuan, northwest China's Ningxia Hui Autonomous Region, Sept. 5, 2019. The fourth China-Arab States Expo has helped promote cross-border high-tech exchange and cooperation. At an exhibition of high technologies and equipment held as part of the expo, visitors are exposed to major scientific and technological breakthroughs and state-of-the-art equipment developed by the high-tech sector. (Xinhua/Li Mangmang)