Padma Shri awardee environmentalist and Odisha's former information commissioner Professor Radha Mohan died while undergoing treatment at a private hospital on Friday, family sources said.
He was 78 and is survived by three daughters.
The Gandhian was in the ICU for the last few days after being diagnosed with pneumonia, hospital sources said.
President Ram Nath Kovind, Prime Minister Narendra Modi and Chief Minister Naveen Patnaik were among those who condoled his death.
Radha Mohan and his daughter Sabarmatee were conferred the Padma Shri last year for their 30-year-long efforts to transform barren lands into a lush green forest in Nayagarh district.
The father-daughter duo had formed a social organization to create awareness among farmers on sustainable organic farming, reported PTI.
Born in 1943 at a small village in Nayagarh district, Radha Mohan had graduated in Economics from SCS College in Puri and completed his post-graduation in Applied Economics from Utkal University in 1965.
After his retirement as the principal of SCS College in Puri, Radha Mohan was appointed the state information commissioner.
Condoling his death, President Ram Nath Kovind tweeted, "Prof Radhamohan was as inspiring an economist as an environmentalist. A profound scholar, he turned to organic farming to enrich nature and humanity. His demise will leave a void. My condolences to his family and followers."
The Odisha government had also awarded him with Utkal Seva Samman for his outstanding social service.
Similarly, UNEP had conferred "The Global Roll of Honour" on Radha Mohan for his distinguished work for the environment.
"Prof Radhamohan Ji was deeply passionate about agriculture, especially adopting sustainable and organic practices. He was also respected for his knowledge on subjects relating to the economy and ecology. Saddened by his demise. Condolences to his family and admirers. Om Shanti," Prime Minister Narendra Modi said in a Twitter post.
Chief Minister Naveen Patnaik tweeted, "Deeply saddened to know the passing away of Gandhian and Padma Shri awardee Prof Radha Mohan. An economist turned environmentalist had distinguished contribution to sustainable organic farming. My thoughts and prayers are with the bereaved family members and well-wishers."
Andhra Pradesh Governor B B Harichandan termed Radha Mohan"s death as an irreparable loss to Odisha"s organic farming sector.
Union minister Dharmendra Pradhan said his commitment towards environment protection and organic farming will always be remembered in times to come.