Water quality in the Three Gorges reservoir hasn’t improved despite efforts to clean up the lake, the Wall Street Journal reported, citing China’s top environmental regulator. A study by the State Environmental Protection Agency said that although US$2.5 billion has already been spent on clean-up projects for the lake, only a third of the projects have been completed. The water quality in the man-made lake created by the construction of the world’s largest dam is good enough for drinking, fishing and swimming. But the water quality of tributaries flowing into the reservoir has deteriorated. Water quality problems could worsen when the reservoir reaches its maximum height, which could occur as soon as this year.