Himachal Pradesh Chief Secretary P. Mitra, who was admitted to the Postgraduate Institute of Medical Education and Research (PGI) in Chandigarh following a brain hemorrhage, was operated upon on Sunday, an official statement said.
Mitra suffered brain stroke on Saturday evening.
State Industries Minister Mukesh Agnihotri visited the PGI and inquired about Mitra's health, the official statement said.
Mitra became chief secretary after his predecessor Sudripto Roy suffered brain hemorrhage in October 2013. After recovering, Roy was appointed as adviser in Delhi.
A 1978-batch IAS officer of the Himachal Pradesh cadre, Mitra took over as regular chief secretary on May 23, 2014 and is to retire in 2016.