Bengaluru’s civic body, BBMP, is exploring an underground tunnel project to tackle worsening traffic congestion. The proposed 14.55-km passage from Hebbal to Silk Board, planned at a depth of 120 feet, has sparked concerns among geologists and environmentalists.

Experts caution that the city’s unique geological makeup could pose significant risks. Bengaluru sits atop a complex terrain where granite ridges separate two major drainage basins—the Arkavathi and Ponnaiyar. The eastern region, dominated by porous saprolites, is particularly vulnerable to structural instability when exposed to water.

The tunnel’s alignment near this fractured rock zone could disrupt the region’s delicate groundwater recharge system. Bengaluru, already struggling with dwindling water reserves, relies heavily on borewells, many of which might dry up if underground water flow is altered.

Additionally, surface water channels, including lakes and stormwater drains, could suffer unintended consequences. With rapid urban sprawl leading to encroachments and poor drainage management, any disruption could intensify flooding in low-lying areas.

Geologists stress the need for an exhaustive study before moving forward. Detailed geological and hydrogeological assessments must determine whether the city’s underground conditions can withstand such a project without catastrophic consequences.

Bengaluru’s rapid expansion, driven by urban ambition, must balance progress with sustainability. Without thorough investigation, the tunnel plan could deepen the city’s water crisis rather than ease its road woes.