Starting in 2015, the school launched a campaign of offering door-to-door education to students who could not attend school because of severe physical disabilities. Xie was among over 30 teachers tasked with tutoring those students. The teachers have trekked over 60,000 kilometers over the past seven years during the campaign because many villages where the students live are located in mountainous areas.

"Although we do feel exhausted sometimes, we feel our work is valuable after witnessing their progress, even just a little bit," Xie said.