Kerala environmental activist Kallen Pokkudan died at a hospital in Kannur district on Sunday.
The 86-year-old, who was known for the conservation of mangrove forests in Kerala, was undergoing treatment at Cherukunnu Mission Hospital in Kannur.
Pokkudan, who started working towards the preservation of mangroves since 1989, has planted over one lakh mangrove saplings across the South Indian state.
Known as Kandal (mangrove) Pokkudan, the green activist has also authored several books. 'Kandal Kaadukallkidayil Ente Jeevitham' and 'Choottachi' are some of his popular works.
In 2014, he was conferred with 7th PS Gopinathan Nair Environmental Award.
He has also played a pivotal role in the Malayalam film, "Papilio Buddha".