BEIJING — Over the past few years, trips back to my home village, Huaihua Di, on the Lanxi River in Hunan Province, have been clouded by news of deaths — deaths of people I knew well. Some were still young, only in their 30s or 40s. When I returned to the village early last year, two people had just died, and a few others were dying.

My father conducted an informal survey last year of deaths in our village, which has about 1,000 people, to learn why they died and the ages of the deceased. After visiting every household over the course of two weeks, he and two village elders came up with these numbers: Over 10 years, there were 86 cases of cancer. Of these, 65 resulted in death; the rest are terminally ill. Most of their cancers are of the digestive system. In addition, there were 261 cases of snail fever, a parasitic disease, that led to two deaths.

The Lanxi is lined with factories, from mineral processing plants to cement and chemical manufacturers. For years, industrial and agricultural waste has been dumped into the water untreated. I have learned that the grim situation along our river is far from uncommon in China.

The nation has more than 200 “cancer villages,” small towns like mine blanketed with factories where cancer rates have risen far above the national average. (Some researchers say there are more than 400 such villages.) Last year the Ministry of Environmental Protection acknowledged the problem of “cancer villages” for the first time, but this is of little comfort to my parents’ neighbors and millions like them around the country.