A 25-year-old man set himself ablaze on Wednesday in the national capital and doctors said he has suffered 90 per cent burns.
The self-immolation occurred at the India Gate lawns where protesters have been demanding the rescinding of the Citizenship Amendment Act.
Police, however, said that the act by the youth, identified as Kartik Maher from Odisha, was not connected to the protests.
"His brother told us that he is mentally unstable," Deputy Commissioner of Police Eish Singhal said.
According to hospital authorities, Maher's condition is critical.
"The man has suffered almost 90 per cent burns and is unconscious. He has been admitted in the emergency ward and is being attended to by doctors. He is critical," Dr Minakshi Bharadwaj, medical superintendent of the RML hospital, said.
A spokesperson of the Union Home Ministry said the self-immolation by Maher is not linked to protest against the amended citizenship law.
The man appeared mentally disturbed, the official said.