The body of Nanu was found this morning by a passerby in a drain, a police spokesperson said.
Injury marks were found on the body after it was brought out, he said.
The victim's family members complained that Gulab Singh (35), the child's uncle, who was allegedly in an inebriated state, last night took the sleeping child with him outside and beat him till he died, the spokesperson said.
Later, he dumped the body in the drain and tried to hide by putting heavy stones and bricks over it, he said.
The police said Gulab, who is absconding since last night, allegedly had some monetary dispute with the victim's family.
An FIR has been registered against the accused, the spokesperson said, adding an investigation is underway.