The study looked at how six lakes in the middle Yangtze River region changed in water quality and nutrients from 2016 to 2020. They found differences between the lakes, with some improving and others getting worse. The main factors affecting the water quality were total phosphorus and a nutrient index. Nutrient pollution increased in some lakes due to high nitrogen and phosphorus levels, while others were affected by things like water flow and pollution control. The study suggests setting nitrogen and phosphorus limits for better lake management. Overall, nitrogen and phosphorus levels were the most important factors affecting the water quality and nutrient levels in the lakes studied during the time period.