CHINA DAILY / REUTERS Workers clear away rubbish along a river in the Chinese town of Rui'an, in Zhejiang province, on Feb. 18, 2013

Jin Zengmin was in a betting mood. Last month, the eyeglass entrepreneur from eastern China’s Zhejiang province announced that he would offer a $32,000 reward to the chief of the local environmental-protection department if he dared to swim in a nearby river for a mere 20 minutes. Jin’s wager, which was announced on Sina Weibo, a Twitter-like social-media service in China, turned viral on the Internet. The environmental cadre, unsurprisingly, declined to swim in the polluted water.

After more than three decades of economic prosperity, China faces serious environmental challenges that are sure to be discussed during the National People’s Congress, the annual conclave currently underway in Beijing. Air pollution blankets hundreds of cities, and the soil in vast parts of the country is contaminated. Thousands of rivers too have been ruined by China’s rapid urbanization and industrialization, like the waterway in Jin’s hometown, Rui’an, a small city near Shanghai that is home to more than 100 shoe factories. “When I was a child, people swam or washed vegetables in the river,” Jin told TIME. “But those factories use chemical raw materials to make shoes and dump their industrial waste directly into the river.”

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In photographs posted by Jin on Sina Weibo, the river surface is covered by floating rubbish. What lies beneath could be even more dangerous. The smell, Jin alleges, is putrid. On Dec 8, Jin’s sister died of lung cancer at the age of 35. He blames water pollution for her death. “When my sister received medical treatment in big cancer hospitals in Shanghai,” Jin says, “we found that many patients there are from my hometown. They have various cancers, and what is astonishing is that most of the cancer patients are in their 30s to 50s. They are still young. I realized these cancers may have something to do with the water pollution in our hometown.”

After Jin’s sister died, he called the local environmental-protection department and asked them to check for water contamination in the river. Jin says he was told by officials that the river was fouled by some household garbage but that the water still met national quality standards. Outraged, Jin took his bet online. Soon, a local newspaper conducted a crude experiment to test the river’s toxicity: they placed a live fish into water fetched from the river. Two hours later, the fish died. “I made my bet because I’m confident the water in the river is poisonous,” Jin says.

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In January, air pollution was one of the hottest topics on Weibo, one of the few public places where Chinese can express their grievances. Faced with citizen outrage, the Beijing government unveiled antipollution measures to try to combat the record smog. February turned into water-pollution month. After Jin’s wager became an Internet sensation, Deng Fei, a Chinese environmental activist, encouraged Weibo users to post pictures of polluted rivers in their hometowns. Thousands of people responded with photographs of fetid local waterways.

Local environmentalists say that China has enough money and technological prowess to clean up its rivers. The missing ingredient for an environmental campaign? Official motivation. Local governments depend on polluting factories to buoy local economies; local bureaucrats know their promotions are contingent on keeping growth rates high. Still, Chinese citizens are no longer sated simply by economic advancement and have taken to Weibo to express their dissatisfaction. “The appeals made by Jin Zengmin and other Weibo users forces people to face up to water pollution and have attracted more people to join the antipollution campaign,” says Ma Jun, a water expert and founder of the Institute of Public and Environmental Affairs. “[Internet activism] can prevent local governments from standing in line with the heavy polluters.”

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Meanwhile, the price of China’s economic success continues to soar. Most of the country’s groundwater is tainted. Smog envelops the eastern seaboard. Soil pollution is pandemic, although just how bad it is few know because the exact figure has been deemed a “state secret.” Environmental whistle-blowers have been beaten and jailed. Many of the protests that have proliferated nationwide in recent years are related to environmental issues. Last June, hundreds of angry villagers from Deyang city in western China’s Sichuan province held a protest march after their crops were destroyed by what they said was industrial waste. The villagers were so angry that they occupied the local government office and clashed with the police.

On Dec. 31, a broken pipe at a chemical factory in central China’s Shanxi province caused a leak of 38.7 tons of aniline, which is used to make industrial chemicals and is toxic to human beings. The aniline spilled into a river that serves as a source of drinking water for more than 1 million people in north China. Yet the local government hid information about the chemical leak for five days. Public outrage ensued, just as it has across the country after countless other environmental nightmares. Asks Jin: “If we Chinese die of cancer caused by pollution, what’s the meaning of economic growth for us?”

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