The incident happened on August 14 when the boy's mother Kashi Bai was crossing the road with the baby in her lap, ASI Shree Bhagwan said.
The mother-son duo received severe injuries in the accident, while the woman was treated in the hospital, the baby succumbed to his injuries, he said.
A case has been registered against the driver of the van with Ballabgarh Police Station under section 279 and 304A of IPC.