The boy has been identified as Kuldeep, a student of Class 7 at a private school.
"Manmohan scolded Kuldeep for scoring poor marks in his exam. Manmohan later left for his work while Kuldeep went to his school," Hardayal Yadav, SHO of Vijay Nagar police station, said.
"After reaching house, Kuldeep hanged himself from the ceiling fan in his room when he was alone at home. The incident was discovered when his sister returned home from her tuition this afternoon. The girl then informed her parents," the official added.
The body has been sent for postmortem examination, the official added.