Senior Congress leader PT Thomas died at 10.30 am on Wednesday. He was 71.

Thomas, one of the popular leaders of the party in Kerala, was undergoing treatment for cancer at Christian Medical College in Tamil Nadu’s Vellore city, Onmanorama reported.

Thomas entered politics through the Kerala Students Union, an arm of the Congress, for which he served in many posts. In 1980, he was selected as the general secretary of the Youth Congress.

Thomas was an MLA from the Thrikkakara constituency in Kerala. He had also been serving as one of the three working presidents of the Kerala Pradesh Congress Committee, according to Onmanorama.

Thomas had represented the Idukki constituency in Lok Sabha in 2009.

He had also worked as the editor and managing director of Veekshanam, a Malayalam daily.

Thomas strongly advocated for environment conservation. In 2011, he had supported the Gadgil Commission, also known as Western Ghats Ecology Expert Panel, when its recommendations for the preservation of the state’s environment had led to protests in the Idukki district.

The report had sought to declare a large part of the Western Ghats as “ecologically fragile”. Several leaders had said that it would stall the state’s development under the name of conservation.

Former party chief Rahul Gandhi said that Thomas was a “superb Congress leader” who grew from the students’ movement.

“He was a forward-looking and open-minded leader who was concerned about the environment,” Gandhi said. “Shri PT Thomas was a huge asset for us. It is a tragedy and we are very sad about losing him.”

Kerala Chief Minister Pinarayi Vijayan said Thomas stood by his political perspective, The Indian Express reported. “In his death, Kerala lost an excellent parliamentarian as well as orator,” said Vijayan.

The Leader of Opposition in Kerala Assembly, VD Satheesanm, said the Congress has suffered an irreparable loss with Thomas’s death.

“I have lost my elder brother,” he said. “He was a Congress warrior who did not compromise on his principles. He was always on the side of the right. He was a model for people like me when he spoke on issues like environmental protection and the security of women. I cannot believe that he is no more.”