About 70 students, including girls, marched to the north gate of the administrative hub and offered support to V Jazeera hailing from Kannur, on Sunday.
Raising slogans in support of the woman, they also tagged a green band around her wrist as a symbol of the environment, students said.
They also recited poems and drew pictures to propagate the message of the need for environment conservation.
Many personalities from various walks of life, including popular actor Suresh Gopi, have offered support to her.
Authorities have, however, denied Jazeera's allegations, saying no illegal sand mining is taking place.