Union Minister Anil Madhav Dave died on Thursday morning. The 60-year-old minister had a heart attack, according to Minister of State Jitender Singh. He was taken to the All India Institute of Medical Sciences where he died, officials told PTI.

“As a mark of respect to the departed dignitary, the Centre has decided that the national flag will fly at half-mast today in Delhi and all state or union territories capitals on all the buildings where it is flown regularly and on the day of the funeral,” a government statement said, according to NDTV. Madhya Pradesh Chief Minister Shivraj Singh Chauhan has announced a two-day state mourning.

On Twitter, Prime Minister Narendra Modi expressed his shock at the sudden demise of his colleague. “I was with Anil Madhav Dave till late last evening, discussing key policy issues,” Modi said. “This demise is a personal loss.” Modi said Dave would be remembered as a devoted public servant. He was tremendously passionate towards conserving the environment, the PM added.

He was a Rashtriya Swayamsevak Sangh member and a Member of Parliament from Madhya Pradesh. His profile on the Environment Ministry’s website described him as a river conservationist, environmentalist, social worker and an amateur pilot. He had taken over as environment minister in 2016.

Dave’s colleagues in the government also expressed their shock and condolences on Twitter and other platforms.