Widespread rural pollution is a major source of pollution for the Yangtze River, the country's longest river, a top legislator said.

"Since the reservoir at the Three Gorges Dam started storing water, the water quality of the mainstream Yangtze River has remained the same, even better. However, minor branches of the river have been polluted by waste from rural areas," said Xie Deti, a National People's Congress deputy and dean of College of Resources and Environment at Southwest University in Chongqing.

"For instance, there is no special treatment for chemical fertilizer, poultry manure, sewage and garbage in rural areas, especially the small farms, which generate direct pollution to water and rivers," he said.