The boy was run over by the vehicle while he was playing outside his home in northwest Delhi's Indira Vikas area on February 9.
As per the victim's family, the cab driver took the child to three hospitals but they refused to treat him.
The family claimed that initially the child was taken to a local dispensary and later to a private hospital and then a government one, but they all turned down the child, police said.
Some of the family members of the deceased claimed that the accused driver had threatened the boy's mother of dire consequences if she reported the matter to police.
"A case has been registered against the driver for causing
death by negligence at the Mukherjee Nagar police station. The child's mother did not mention that she was threatened by the driver while giving her complaint. We are investigating the matter," said a senior police officer.