The correct answer is that the decrease in hydropower developments is not a major reason for increasing water pollution of the Yangtze river.
The Yangtze River is a long river in China, the largest in the country and the Asian continent, which flows from Tibet to the sea, near Shanghai. It has a length of 6300 km, the third longest in the world, after the Amazon and the Nile.
40% of the country's waste is discharged into the river, about 25 billion tons per year. One third of the contamination would come from fertilizers and chemical products, pesticides and agricultural residues; the rest would come from the cities, from the industrial sector and from the boats that sail along the river. In addition, these waters are considered the most turbid on the planet, with sediment transport estimated at 680 million tons per year.
Regarding the Three Gorges Dam, the environmental consequences in the place have been devastating. One example is the recent extinction of the Baiji or Chinese dolphin, an endemic species of the Yangtze River, which had been in critical danger of extinction for decades due to the water pollution. The construction of this dam has taken to the limit the conditions that this species of dolphin could support, and finally, in 2008, after exhaustive searches, the baiji was declared officially extinct.
