The man, identified as Ashok Kumar, was sacked from his services in BSF in the year 2000 after he was declared mentally unstable, police said.
According to police, Kumar, along with his wife and three children, came to Vijay Chowk this afternoon and poured kerosene on himself. However, he was prevented by security officials, deployed at the spot, from self-immolation, police said.
Kumar was then taken to Parliament Street Police station. He was sent for a medical examination to ascertain if he is mentally ill or not, police said.