"Since Dongting Lake is so large, the authorities were unable to stop many of the illegal activities taking place. But He and many other fishermen familiar with the area helped them," Liu says.
The work upset some people, especially those with a vested interest. He and many of the other volunteers received death threats. As the documentary shows, this prompted the association to pledge to take care of families in the event of the sudden death of one of their members. He and his friends still live a relatively poor life but continue to work on protecting the environment.
The documentary was filmed over five months, during which crew members were separated into three groups-interviews, location shoots and storytelling.
Chen says they used the latest technology to obtain the best shots, including drones and the ARRI Mini, a camera widely used in filmmaking.
"In our group of seven people, we traveled to more than 20 cities with packs weighing 200 kilograms. Sometimes we had to hike for hours in the mountains or walk on rough roads, but no matter how tired we were, we felt very excited whenever we found a great angle to shoot from."
Li Yi, the production planner of the documentary, says they are making an English version of the series and will promote it in overseas markets after adding more background information.
"We find it hard to tell stories about China to an overseas audience on many themes due to cultural differences, but this one focuses on the environment, a universal topic around the world," Li adds.
The documentary has been welcomed by viewers across China, Chen says.
"We want to show viewers that the river has changed tremendously, and many people put a great deal of effort into bringing about that change."
