The former Union Minister E. Ahamed suffered cardiac arrest in Parliament when President Pranab Mukherjee was delivering his address to the joint session at the start of the Budget session on Tuesday.
He was immediately taken to hospital, and his condition is critical.
Mr. Ahamed, 78, president of the Indian Union Muslim League, complained of breathlessness and uneasiness.
The staff at Parliament tried to administer first aid, but it did not help.
He was rushed to Ram Manohar Lohia Hospital, where he has been under intensive care and on life support.
Mr. Ahamed, MP for Malappuram in Kerala, was Minister of State for External Affairs in the United Progressive Alliance government.
On ventilator support
He underwent a procedure to revive his heartbeat and was put on ventilator support in the hospital.
Prime Minister Narendra Modi enquired about his condition.
Congress vice-president Rahul Gandhi and Union Minister of State for the Prime Minister’s Office Jitendra Singh visited the hospital.