Bengaluru's tunnel road project threatens Lalbagh ecosystem, warn greens

Bengaluru: Environmentalists and citizen activists fear the proposed tunnel road project could spell disaster for Lalbagh — Bengaluru's treasured green lung and a living symbol of its heritage.

The alignment of the controversial 17km tunnel road project connecting Hebbal and Central Silk Board passes directly beneath Lalbagh in south Bengaluru. Activists warn that the project would require the acquisition of six acres of Lalbagh land, causing irreversible damage to its delicate ecosystem.

The land would be acquired along the 1.1km Siddapura Road between Ashoka Pillar and Marigowda Junction. Plans show that two massive tunnels will run below the garden, with two connecting ramps and a large ventilation shaft proposed within the premises. The tunnels are expected to be constructed at depths ranging between 50 and 100 metres beneath Lalbagh.

The activists fear that the massive tunnel construction could have a far-reaching impact on the Lalbagh Rock — a Peninsular Gneiss National Geological Monument estimated to be around 3,000 million years old. Atop this ancient hillock stands a 16th century watchtower built by Kempegowda, which once marked Bengaluru's southeastern boundary. As part of the project, two 15-metre-diameter tunnels and two 10-metre-diameter ramps are proposed to be built through this ancient rock using massive tunnel-boring machines. A large ventilation shaft is also planned nearby.

Environmentalist Dr Yellappa Reddy said, "The Dharwad craton system, which extends from MM Hills all the way to Ballari, protects peninsular India from earthquakes. Parts of this belt have already suffered extensive granite extraction. A rupture of the Lalbagh rock could even cause water from Lalbagh lake to seep into the Nimhans complex. Tunnel constructions will also pose a risk to hundreds of buildings along the alignment. I strongly urge that the National Institute of Rock Mechanics be consulted before even considering such projects."

Rajkumar Dugar, founder of Citizens for Citizens (C4C), said the proposed tunnel work could also affect 40 acres of Lalbagh lake. He added that the tunnel's entry point from Ashoka Pillar lies less than 100 feet from the lake's edge, raising serious concerns about potential ecological damage.

Dugar also accused the detailed project report (DPR) of being silent on the removal of trees in the botanical garden.

Proposed constructions

The entry ramp to the proposed tunnel roads at Lalbagh will be 1.4km long, starting about 50 metres from Ashoka Pillar on the Lalbagh side of Siddapura Road. Vehicles from multiple directions will converge onto Siddapura Road via Ashoka Pillar to access the ramp, raising concerns about potential traffic gridlock in the area. The exit ramp at Lalbagh will be 1.1km long, ending near Marigowda Junction on Siddapura Road.

At least a 100m x 50m area, near Siddapura Road, inside Lalbagh, will be used for a ventilation shaft to ventilate around 2-4km of tunnel on each side, both towards Central Silk Board and Hebbal. "This shaft will be like a chimney inside Lalbagh — throwing out heat, exhaust gases, lowering Lalbagh's air quality, and raising noise pollution," according to a press release by Citizens for Citizens.

——-

Quote

Trees within the six acres of land required for the tunnel road project will have to be removed but DPR is silent on their number and other details

Rajkumar Dugar, founder, Citizens for Citizens