One of her most popular series of images is about a hunyu (marriage and childbirth) school in Northwest China. Such schools were established across the country around the 1980s when the national policy of family planning which limited couples to just one child had been implemented to curb the rapid population growth. The schools helped educate and provide child-rearing information to newlyweds.

"On its white-and-green wall, there is illustrated information about sex education, birth control, healthcare during pregnancy, as well as good parenting, which, even today, are not out of date," Zhao says.

A Xiaohongshu user named Sanwenyu Fanfan agrees that such schools should also be promoted today to teach people how to become qualified parents.

Zhao says that although such schools or institutions have disappeared, their existence bears witness to changes in the country's family planning policy that was in effect for decades.

That policy has gradually eased due to current social circumstances and widespread concerns over the country's low birthrate and aging society. Earlier this year, the National People's Congress, China's top legislature, responded by amending the law to encourage couples of childbearing ages to have three children.