A proposed underground corridor linking south Delhi with the Dwarka Expressway is set to affect nearly 1,500 trees more than triple the initial projections raising fresh questions about ecological trade-offs in large urban transport projects. The revised estimate has emerged as planning discussions advance for the NH-148AE corridor, a five-kilometre stretch intended to streamline access between Nelson Mandela Marg and the airport zone.
The project, led by the National Highways Authority of India (NHAI), aims to ease congestion on arterial routes connecting Dhaula Kuan, Mahipalpur and Indira Gandhi International Airport. Officials involved in inter-agency coordination say the jump in tree impact follows alignment modifications and updated engineering assessments. The tunnel proposal remains under preparation of a Detailed Project Report (DPR), which will determine its technical feasibility and financial viability.
Beyond the tree count, the scheme requires the transfer of approximately 2.6 hectares of land from the Delhi Development Authority after route realignment. Utility relocation is another major component: water supply, sewer networks and high-tension power lines along Nelson Mandela Marg would need to be shifted at an estimated combined cost exceeding ₹20 crore. Such civil adjustments often influence timelines and overall capital expenditure in dense urban settings. Environmental oversight bodies have flagged that parts of the corridor intersect with land classified under the southern Ridge Delhi’s largest contiguous green belt as well as a patch categorised as deemed forest. In total, nearly 7.5 hectares fall within environmentally sensitive zones. Urban planners note that while tunnelling can reduce surface-level disruption compared to elevated highways, portal construction, ventilation shafts and approach ramps still require surface clearance.
The Delhi tunnel project arrives at a time when the capital is balancing infrastructure expansion with climate resilience commitments.
Road-based connectivity to the airport is economically critical for trade, tourism and logistics. However, the southern Ridge functions as a vital carbon sink and biodiversity buffer in a city grappling with chronic air pollution and urban heat stress. Transport economists argue that faster airport access could yield productivity gains and decongest established bottlenecks. Yet environmental analysts caution that tree loss at this scale demands transparent compensatory afforestation plans, long-term monitoring, and alignment with Delhi’s broader zero-emission mobility roadmap. Investment clearance for the Delhi tunnel project will depend on traffic projections, cost-benefit analysis and integration with national infrastructure planning frameworks. As the DPR advances, the decision will test how India’s capital reconciles growth-led connectivity with the preservation of fragile urban ecosystems an equation increasingly central to sustainable city-building.
Delhi Ridge Faces Pressure From Tunnel PlanÂ
