HUANGMENGYING— Liu Yuzhi can barely stand. To walk, she needs to lean on a bamboo stick. Her emaciated face is covered with red stains and her hips are deformed by illness. She is 42 years old but she looks 30 years older. "About 10 years ago, I started feeling pain all over my body. The hospital diagnosed me with bone cancer," she explains in a strained voice.

Her husband had to stop working to care for her. "Financially, it's very hard," he says.

Liu Yuzhi lives in the rural hamlet of Huangmengying, in eastern China's Henan province​, on the Huai river — one of China's most polluted. Huangmengying is one of the 459 "cancer villages' in the country. "Since 1992, more than 140 out of 2,800 people in this region died of cancer," says Huo Daishan, an ecologist trying to raise awareness about this issue. "This street is called the "cancer alley" because each house holds at least one victim."

In China, about 190 million people drink contaminated water.

Victims of Huangmengying fall ill because of the river's pollution. "The water they are drinking comes from the well filled by this river. They're eating fish caught in this same river and the vegetables are irrigated by the same water," he says. In China, almost 60% of underground water, 30% of rivers and 19% of cultivated soil are so polluted that they are deemed dangerous to humans. One out of seven people in China, or about 190 million people, drink contaminated water. The soil contains chemicals like mercury, lead and arsenic.

Huai is not the only contaminated river. The Yellow River, Yangtze and the Pearl River are among the most polluted rivers in China. Their banks hold factories of paper, leather, paint and pesticides. "These factories usually throw away their waste in the river," says Huo Daishan. It's not unusual for a putrid layer of moss to cover the Huai river and for the water body to turn red or black. A couple of years ago, six peasants died after using polluted water to irrigate their crops.

Rice laced with arsenic

In addition to industrial pollution, pesticides and fertilizers used by farmers leach into rivers and lakes alongside fields, says Andreas Holback, a German biologist studying water pollution in China. Some of the toxic products in Chinese water bodies can cause cancer in digestive organs such as the stomach, throat, and the colon. Part of the rice cultivated in this region is contaminated with arsenic.

Smog on the Huai river — Photo: Zhu Haijun/Xinhua via ZUMA

To get to the village of Wazi, which lies about 20 kilometers from Huangmengying, people cut through rapeseed fields along a smaller river. Its grayish water is full of trash: old, torn clothes, plastic bags, used notebooks. "We asked local authorities to come and pick up the trash but they told us it was too expensive. So we have no choice but to throw everything out in the river," says an old man from the village. According to a 2013 study by the Chinese Center for Disease Control and Prevention, the cancer rates in the area along Huai river were 50% higher than in the rest of the country.

China's Erin Brockovich

Facing environmental disaster, some have chosen to resist. Wei Dongying is one of them. She lives in the village of Wuli near Qiantang river, which borders 300 textile factories that manufacture clothes for Western labels and routinely discharge sewage into the water. Wei Dongying, often called China's Erin Brockovich, started investigating the deaths of her neighbors in the early 1990s. "More than 60 people died from cancer between 1992 and 2004 here. After that, the government stopped providing data," says the 47-year-old fisherwoman as she wanders around the factories built right behind her house. "But last year only five to six villagers died of cancer."

The cancer rates in the area along Huai river were 50% higher than in the rest of the country.

The air is saturated with the smell of detergent and chemical products. Wei Dongying has collected dozens of samples of polluted water. She also has a large collection of photographs she took over the years. Some show boiling black water spurting out of a factory pipe. Others reveal a canal full of orange-colored water. "Today, factories take care not to pollute during the day but when I'm fishing at night, I can see them pumping waste into the river."

In June 2015, she filmed a worker at one of the factories saying that his employer has two pipes, one for treated water and another for polluted water. When environmental inspectors pay a visit to the factory, they show them the clean pipe but the rest of the time they use the dirty one.

Wei's activism has made her a target. Her phone is under surveillance and she has been arrested dozens of times. Last December, she says she spent 10 days in prison for filing a complaint against a detergent factory. "The government is obsessed with economic growth and, meanwhile, we ordinary citizens pay the price," she says.