Parameswaran, former nuclear scientist who later became prominent as a Marxist theorist, people’s science movement activist and writer, passed away in Thrissur, Kerala, on Tuesday (August 11, 2026). His ideas on the ‘fourth world’ had triggered wide debate and eventually led to his expulsion from the CPI(M) in February 2004. Mr. Parameswaran was instrumental in the formation of the All India People’s Science Network (AIPSN), a network of people’s science organisations spread all over the country. Book triggers debateMr. Parameswaran’s book Fourth World triggered a massive debate within the CPI(M), of which he had been an active member. In February 2004, the CPI(M) expelled Mr. Parameswaran on serious charges of indiscipline, finding that he had deviated from the party line.