Dont ignore eco-study for Bengalurus NorthSouth tunnel, warn experts

BENGALURU: As Bengaluru prepares for its longest tunnel road project between Hebbal and Silk Board (North-South tunnel), environmental experts warn that ignoring a full Environmental Impact Assessment (EIA) could expose the city to geological risks, water loss and safety concerns. The Bruhat Bengaluru Mahanagara Palike (BBMP) had commissioned Altinok Consulting in 2024 to study tunnels, elevated corridors and other decongestion projects. The report recommended a detailed EIA. However, the final Detailed Project Report (DPR) prepared for the 16 km project states that under the EIA Notification, 2006, and subsequent amendments, tunnels are not classified as projects requiring clearance. Environmentalists, however, argue that bypassing impact studies for Bengaluru could have serious consequences. Speaking to The New Indian Express , AN Yellappa Reddy, former secretary to the Department of Ecology and Environment, said that a full impact and risk assessment must be conducted before starting excavation. Cutting through granite bedrock with blasting can affect nearby high-rise apartments. Continuous blasting will disturb underground fissures and fractures that connect to recharge systems and aquifers, he explained. Reddy elaborted that Bengalurus groundwater exists in layers of dynamic, static and fossil water, ranging from 50 to 1,000 feet deep. If static water is drained, voids are created. These can trigger unpredictable risks during mild earthquakes. It could become one of the citys biggest man-made blunders, he warned. Authorities cannot use the 2006 EIA exemption to avoid accountability, he said, adding that precautionary principle and Supreme Court orders require risk analysis. On the roads, pollution at least disperses into the open air. Inside a closed tunnel, emissions like carbon monoxide and nitrogen oxides will accumulate, turning it into a death chamber. Ventilation ducts may push these pollutants out, but that only creates concentrated hotspots of toxic air at the tunnel exits, adding a new layer of environmental risk for nearby neighbourhoods, said Sandeep Anirudhan, convenor - Coalition for Water Security and Citizens Agenda for Bengaluru, and called for an EIA to at the least get an idea of what they are dealing with. The Ministry of Road Transport & Highways (MoRTH) has listed EIA as part of the checklist for submission of long tunnel (more than 1.5 km) project proposals on national highways (issued on 24 October 2024), following the Silkyara tunnel collapse incident in Uttarakhand.