MUMBAI, Nov. 23 -- Fresh dumping of debris, excavation and concreting along the banks of the Chena river near Ghodbunder Road over the past two days have triggered concerns among environmental activists, who say the work violates multiple environmental rules. Videos captured this week show JCBs digging through grasslands, mangrove roots exposed, debris pushed into the river and concrete embankments extended along the water's edge. Complaints about these violations were filed on Friday and Saturday with the Thane deputy conservator of forests, the Maharashtra Pollution Control Board (MPCB) and the Mira-Bhayandar Municipal Corporation (MBMC). The activity is part of the Chena Riverfront Development Project initiated by Shiv Sena MLA Pratap Sarnaik, in which long stretches of the river have been concreted and sections opened to the public. The project received clearance from the Eco-Sensitive Zone Monitoring Committee in March last year. Activists emphasised that the committee's approval did not permit actions that are explicitly banned. "The law does not allow debris-dumping, mangrove removal or altering a riverbank. The work violates the Construction and Demolition Waste Rules, 2016," said Nishant Bangera, founder of the NGO Muse Foundation. Bangera said that almost the entire belt fell either under eco-sensitive zone 2 (ESZ-2). The activist warned that concreting the riverbank would disrupt natural drainage. "They have dumped debris across mangrove patches and are decorating them with plantations," he said. "All these small channels feed the Chena river. Encroachments along them leave no space for water to move, and Ghodbunder Road floods repeatedly. Concreting the bank guarantees more flooding." Environmental activists pointed out that the Chena, in the Sanjay Gandhi National Park (SGNP) buffer zone, was among the last relatively undisturbed rivers emerging from the park, with intact grasslands, trees and riparian vegetation. Much of the debris has also been dumped along the SGNP boundary. "The Chena is a river where you cannot concretise its banks or destroy mangroves. These are gross violations," said activist Stalin Dayanand, director of the NGO Vanashakti, who has filed complaints with various government institutions on this. Officials from the committee declined to comment on the issue. MBMC officials didn't respond to calls from HT....