Former prime minister Atal Bihari Vajpayee, who was admitted to the All India Institute of Medical Sciences (AIIMS) for over nine weeks, passed away on Thursday, an official statement from the premier medical institute said. The 93-year-old veteran Bharatiya Janata Party (BJP) leader was in a critical condition and was continuously on advanced life support. His medical condition deteriorated in the last 48 hours, the doctors said.