Excavation of 15,000 cubic meters of the natural riverbed would change the natural course of the river, leading to flash floods, the petition alleged.
No prior environmental clearances have been sought for the activities being undertaken by the Mithi River Development and Protection Authority (MRDPA) and the Mumbai Metropolitan Region Development Authority (MMRDA), the NGO claimed.
Counsel for the NGO, on Thursday, submitted that the authorities have, so far, carried out nearly 100 powerful blasts in the riverbed without conducting environmental impact assessment. The blasts could have an adverse impact on the mangroves, he alleged.
Kiran Bagalia, counsel for the MMRDA, submitted that the authorities have undertaken the blasts in accordance with the recommendations of an expert body and it would not cause any harm to the mangroves.
The petition states that the project envisages rehabilitation and revival measures for the river without effectively addressing the illegal discharge of poisonous and toxic effluents. It seeks to enhance the sewerage carrying capacity of the river by widening and deepening its natural riverbed, it added.