Local people had complained about the 22-year-old man being a nuisance, throwing stones and contaminating the public water tank with filthy materials, police said.
Irked by this, the man allegedly poured boiling water on his son when he was fast asleep yesterday.
A case was registered against him under the Mental Health Act 1987, police said.
The man, who suffered serious burns, has been admitted to the Government Rajaji Hospital here.