BEIJING — The Chinese Ministry of Environmental Protection has issued an order preventing dam-building on a stretch of the upper Yangtze River, according to environmental activists, that will result in the scrapping of a proposed dam near the western metropolis of Chongqing that had been opposed for years by environmentalists.
The would have cost billions of dollars to build and operate, and it was supported by , the former Chongqing party chief who was in 2013 for corruption. The dam would have been Chongqing’s largest infrastructure project.
Environmentalists said the dam would have destroyed a protected area of the river that had been established by officials as an ecology-friendly counterpoint to the construction of the , farther downstream and the world’s largest hydropower project. The protected area has been a haven for a wide variety of fish — some of which are rare or endangered — that need access to rapidly flowing waters.
Sections of the Ministry of Environmental Protection’s order were posted on microblogs this week by environmentalists who had gotten copies of the document. The order was dated March 30. Zhang Boju, an advocate at Friends of Nature, a nongovernmental organization that has been a persistent critic of the dam, said in a telephone interview that he and other environmentalists had posted sections of the document online and that he was certain they were authentic.
The ministry declined to comment on the order.
Mr. Zhang said the building of the Xiaonanhai Dam would have set a dangerous precedent because its construction would have meant that the designation of natural areas as protected zones carried no weight.
“If the Xiaonanhai Dam was built, the entire protection zone would be destroyed, and the protection-zone system would be rendered meaningless,” he said.
While Mr. Bo governed Chongqing, the largest municipal area in China, the government there worked to try to shrink the protected area along the Yangtze to remove roadblocks to dam construction. In December 2011, the State Council, China’s cabinet, approved a proposal to shrink the preserve.
It is unclear to what degree the downfall of Mr. Bo contributed to the ministry’s order to cancel dam construction. The murder scandal that led to Mr. Bo’s ouster from the party and imprisonment began in February 2012, when the police chief of Chongqing fled to a nearby American Consulate to tell diplomats there that Mr. Bo’s wife, Gu Kailai, had killed a British businessman whom the Bo family had known for years. When Communist Party leaders learned of the accusations, they ordered the arrests of Mr. Bo and Ms. Gu and put each of them on trial, though only Ms. Gu was .