The water quality in Weihe River Basin in Shanxi Province has been studied over the past 20 years. The researchers found that the water quality has been deteriorating over time. The upstream areas have better water quality compared to the Xi'an and Xianyang sections, which have severe water pollution. Human activities and natural processes are causing significant changes in water quality. It is crucial to take effective measures to prevent further deterioration of water quality in the Weihe River Basin.