"China once invested a lot of money in improving local life in various aspects, from transportation to medical service and education, but the poverty problem couldn't be fundamentally solved, even with such efforts. And relocation has proved to be the most effective way to fight poverty."

Zhang says the idea of producing the documentary was promoted during the Guangzhou International Documentary Film Festival in 2016.

"Since then we have set the tune to tell all stories from individual perspectives, with a grand-theme backdrop," says Zhang.

Aside from the Metog episode, the documentary has turned its lens on a poor village in the Lyuliang Mountains in Shanxi, the ethnic Nu people living in the Nujiang Canyon area in Yunnan, and fishermen and their families who previously lived in boats on Honghu Lake in Hubei.

"Every story took more than two years to shoot, with the longest being four years. Time offers us a wide perspective to observe a transformation, which makes up one of the most valuable elements of a documentary," says Zhang.

"You will be touched to see that, even while living in poverty, the villagers kept their faith in tradition and love. They couldn't choose where they were born but they worked hard to pursue a better life. For us, that is worth recording."