During the ten-year Cultural Revolution, a.k.a. The Great Proletariat Cultural Revolution (伟大的无产阶级文化大革命), education system for the most part became paralyzed and literally came to a halt for a while, college professors as well as school students were sent to the countryside to be “re-educated” (接受再教育), thus the term “the sent-down youth” (知识青年上山下乡); later as the education reform continued, schools began to enroll “workers, peasants, and soldiers” as college students;
See how this education reform is represented in the film “Breaking from the Olds“.