An exhibition showcasing Mongolia's advanced water-saving technologies and products opened here Wednesday to observe World Water Day, which falls on Friday.Addressing the opening ceremony, Minister for Nature, Environment and Green Development Sanjaasuren Oyun said Mongolia was facing serious land desertification and water shortage, a phenomenon now threatening national security.The exhibition aimed to promote the use of water-efficient products and raise public awareness of the need for a water-saving society, she said.The three-day event also features a series of seminars on water conservation.In recent years, water scarcity has increasingly become a bottleneck to the development of Mongolia, where land desertification is expanding at an alarming rate, especially in its mineral-rich southern Gobi area