According to Sub Divisional Magistrate Satender Duhan, Sumit accidentally fell in the open sewerage line at about 9 PM.
Rain had made the ground slippery and a lot of water had accummulated in the sewarage line, the SDM said.
Police took out the child's body after an hour's struggle, Duhan said.
Sumit was taken to ESI hospital, Manesar, where he was declared dead, he said.
Gurgaon Deputy Commissioner P C Meena ordered an inquiry to be conducted by SDM into the incident.
