A study compared water conditions in Taihu Lake before and after 2000. By analyzing water data and quality in different areas, researchers found more water coming into the lake post-2000 due to Yangtze River diversion. This led to increased pollution entering the lake, causing more significant unhealthiness in the water. To fix this, controlling pollution from land and the Yangtze River diversion is vital to decrease pollutants in various parts of Taihu Lake.