片名：《溯 Trace to the Source》
The Tuotuo River, which belongs to Tanggula Mountain Town, is the positive source of the Yangtze River. In recent years, with the development of the economy, the number of people entering the Qinghai-Tibet region has been increasing. However, uncivilized behaviors such as littering have caused serious damage to the ecology of the source of the Yangtze River. Facing the environmental crisis, Green River volunteers from all over the world took on the important task of saving the source of the Yangtze River.