"The child fell into the abandoned borewell when he was playing this morning," Assistant District Fire Officer Murugesan told PTI.
The mishap happened at Koorampadi village in Arcot taluk here and local authorities alerted the Fire and Rescue Services and NDRF officials.
"The borewell is approximately 250 feet deep and the child is struck at about 20 feet and we are hopeful of rescuing the child," he added.
The borewell was abandoned after water had dried and the opening left open, the official said.