The 92-year-old former general secretary of the CPI suffered a paralytic stroke yesterday and is reportedly "critical".
"I have directed the authorities of GB Pant Hospital to provide best possible treatment to veteran leader AB Bardhan. He is still critical," Delhi Health Minister Satyendar Jain said tweeted.
Politicians including - NCP chief Sharad Pawar, CPI(M) parliamentarian Mohammed Salim and party politburo member Brinda Karat, trade unions and Left cadre activists - were amongst those who visited the hospital to enquire about Bardhan's health.