Yin Jun, photographer. [Photo by Yin Jun/Provided to China Daily]

"It is an open-air Sunday farmer's market under Shuangbei Bridge," Yin says. "There is no lighting system so vendors have to arrange their own lights for the stands when the day is still dark."

He found a young woman as she was busy piling up vegetables with both hands and used her mouth to hold the torch.

"I was touched by her diligence," he recalls. "I got her permission to take the pictures. I also bought some vegetables from her."

Another photo tells the story of an old migrant worker who slept under the Jialingjiang bridge to save money. Many poor people from rural areas in China come to big cities like Chongqing to find jobs.

In 2015, Yin finished his morning swim in the Jialing and found the old man, in his 50s, washing his face by the river. The migrant worker's simple luggage was packed under the bridge.

"Some of my friends knew this man and told me his story," Yin says. "I didn't want to bother him and for six days I tried to find a good angle to take pictures."