From the Beijing Star Daily, via sina.com (in Chinese), translated by CDT (link):
Three elementary school students were punished to take off their pants for failing to finish their homework the day earlier in Wuchuan City, Guangdong Province. The teacher, Ms. Chen, discovered three of her students didn’t finish their homework, and asked them to go to her home to finish the work. When they couldn’t finish in a couple of hours, the teacher asked her students to take off their pants and sent them home unclad from waist down. The parents were angered and called the principal, who said would look into the matter and asked the teacher to apologize to the students and parents.