The boy, a class I student, suddenly collapsed in the second-floor corridor of Pawar Public school in Powai at around 10 this morning when he and some other boys were playing during the recess, police said.
He was rushed to a hospital where he was declared 'brought dead', said senior inspector A Dharmadhikari of Sakinaka police.
According to his parents, the boy wasn't suffering from any disease.
The cause of death will be known after autopsy report becomes available, the officer added.
Deputy Commissioner of Police (zone 10) N D Reddy and Assistant Commissioner of Police Sanjay Patil visited the school after the incident.
Police went through CCTV footage of the spot and spoke to the school staff, said another police official.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)