A high school in Jinggu county, Southwest China’s Yunnan province, punished three students for bringing cooked food contained in paper bowls and plastic bags into the classroom, the Southern Metropolis Daily reported on Friday.

Li Guohua, deputy head of the school, said the school has banned students from eating food packed in plastic bowls or plastic bags in dorms or classrooms because many students buy takeout from fast-food restaurants and litter, messing the campus with plastic garbage.

The three students will attend the school for another six months under surveillance and will be allowed to continue their study if they behave well during this period, said Li.