The man, identified as Heera Lal, a resident of Tahirpur leprosy clinic in west Delhi, died at 3.10 am. He had suffered 80 per cent burn injuries, a senior police officer said.
Following the incident, yesterday, Lal was admitted to the RML Hospital for treatment.
In a suicide note, he had alleged that he was tired of the frequent fights with his neighbours and was ending his life, the police said.
The note was found near the place where he had poured petrol on himself, they said, adding that his family members and neighbours have been questioned.
He was a student at a government school here and had three siblings. His parents are suffering from leprosy.