Yemeni students do exercises at a school in Sanaa, Yemen, Sept. 15, 2019. The new school year in primary and secondary schools for 2019-2020 in Yemen started on Saturday. (Photos: Xinhua)

Yemeni students attend a class at a school in Sanaa, Yemen, Sept. 15, 2019. The new school year in primary and secondary schools for 2019-2020 in Yemen started on Saturday.