The study looked at how different types of land use affect the water quality in the Yangtze River basin from 2006 to 2018. They found that water quality has improved over time, especially in the tributaries. Pollutants are higher in tributaries compared to the main rivers, and closer to the estuary. Forest and grassland help clean the water, while agricultural and construction land make it worse. Chemical oxygen demand is more affected by land use than ammonia. This information can help manage land and control pollution better.