After discussing with his parents and carefully mulling it over for two months, he decided to do something meaningful for society and applied to a two-year volunteer program (run by the Communist Youth League of China and the Ministry of Education) introduced in 2003, calling for graduates to provide volunteer services in western regions. More than 370,000 graduates have attended the program in the past 18 years.

After finishing the two-year teaching program at Youqi Village Primary School in the mountainous Dahua Yao autonomous county in Guangxi in 2013, Hou found a job in Shenzhen.

When his bus was leaving, he realized that scores of children were running behind it pleading with him not to go. His tears fell heavy and hard.

"I just cannot leave these children," Hou says. He returned to the school three months later.

Now, he is in his 11th year as a volunteer teacher in the impoverished area.