Zhang Yuchen reports on the grim plight that faces 'left-behind seniors'.

Cheng Deguang often spends half his day sitting on the banks of the river that connects his village to the city of Jinan in Shandong province. Sometimes, Cheng stares at the water for hours, immobile as a statue. When the temperature begins to fall, he moves inside his house about 1 km from the riverbank.

The 82-year-old farmer and his wife, 72, live on a small piece of land in Huaerzhuang, a village close to the banks of the Yellow River. He can usually count on seeing his oldest son at least once a year, but his younger boy, who works in Shenzhen, Guangdong province, has not returned home for several years.

Although Cheng misses his sons and worries about their lives, his greatest concern these days is the safety of his wife and himself. Last winter, when Cheng was out selling peanuts he had harvested, his wife fell as she attempted to collect firewood near the riverbank.

The mishap occurred in the evening when most people had headed home for supper. With no one to lean on, Cheng's wife stumbled step by step to their house. The pain in her swollen ankle lasted until dawn next day.

Although the incident had no long-term ramifications, and could have happened to almost anyone, it highlights the plight of elderly people living in rural areas.

More than 160 million seniors live in the countryside and 90 percent of them have seen their children move to the big cities in search of work.

Shi Fuzhu and his wife Xie Taohua replace a damaged light at their home in Chongan village in Ningxia. All their three children work in big cities and rarely return home. Peng Zhaozhi / Xinhua

Of those 160 million, 34 percent have been the victims of attacks or have had accidents, large or small, during the past two years, according to a provincial aging bureau in Shaanxi province.

A sense of foreboding also hangs over the elderly rural poor. Last month, seven seniors were murdered within the space of two weeks in the backwoods of Shaanxi province. Some experts saw the tragedy as a warning of the serious security issues facing elderly people left to fend for themselves in the countryside.

In early April, Chen Jun, a 20-something who had just been released from prison, arrived at Heigou village in mountainous Shangnan county, an isolated spot in Shaanxi. Early in the evening, under the pretext of buying sheep, Chen knocked at the door of Sun Kaicheng, a 59-year-old who lived with his wife, 49.