The proposed Bengaluru tunnel road is moving through its planning and execution process while the Karnataka State Pollution Control Board (KSPCB) says it has not assessed the ecological impact of underground excavation or received such an assessment from another agency. The disclosure, made in response to a Right to Information application, raises a larger question about how the city evaluates environmental risk when major urban infrastructure falls outside the conventional approval framework.
The project is a proposed 16.7-kilometre tunnel road connecting Hebbal and Central Silk Board. It is being managed by Bengaluru Smart Infrastructure Limited, or B-SMILE. The route is significant not only because of its scale, but also because underground construction can interact with the ecological systems above and below ground. The RTI application specifically sought information on possible effects on the flora, fauna and groundwater table of Lalbagh Botanical Garden, one of Bengaluru’s sensitive green assets.
KSPCB’s response said it had no internal evaluation reports, inspection notes, technical assessments or correspondence on the ecological impact of the proposed excavation. It also said it had not received an Environmental Impact Assessment or a Rapid Environmental Impact Assessment report for the project. The information was provided to Varsha, a Padmanabhanagar resident, whose application sought certified digital copies of any such studies.
That absence does not by itself establish that the tunnel road will damage Lalbagh, groundwater reserves or other ecological assets. It does establish that, at the time of the RTI response, the state pollution control authority did not possess the assessments that would allow those risks to be examined through its records. The distinction is important: the issue is not a confirmed environmental impact, but the lack of documented scrutiny available with the agency approached for it.
B-SMILE has offered a different explanation for the timing. Dr B S Prahalad, its Technical Director, said the assessments sought under the RTI application form part of the project’s Environmental Management Plan. According to him, KSPCB and other approvals would be sought after the project is awarded and the final design is ready. He said it was too early to begin the process, which would take place at a later stage.
This position places the environmental assessment within a later stage of project development, after the award of the work and completion of the final design. The administrative sequence matters because the scope of environmental scrutiny depends on what is finally designed, where construction shafts and access points are located, how excavation is managed and what safeguards are proposed. At the same time, delaying the assessment means that the public record currently does not show how the project could affect the ecological assets identified in the RTI application.
The regulatory question is complicated by the project’s classification. B-SMILE said a standalone tunnel project such as the one proposed in Bengaluru does not require prior EIA under the notifications issued by the Ministry of Environment, Forest and Climate Change and subsequent amendments. Dr Prahalad said prior EIA is required for projects covered by those notifications, but that a standalone tunnel is not included in the requirement.
This creates a gap between what may be legally required under the existing notification and what may be necessary to understand the urban consequences of a large project. A project can fall outside a formal prior-EIA category while still affecting systems that do not respect administrative boundaries. Groundwater movement, tree roots, surface drainage and the ecological functioning of green spaces are not confined to the exact footprint of a road or tunnel portal.
The RTI response therefore brings institutional responsibility into focus. KSPCB is the authority whose records were examined, but the response does not establish that no environmental work exists anywhere within the government system. It says the Board has not conducted or received the specified assessments. B-SMILE, meanwhile, says the relevant studies are linked to the Environmental Management Plan and will be pursued later. The available evidence points to a sequencing issue: the regulatory authority has no such material now, while the project agency says it belongs to a subsequent stage.
For Bengaluru, this is not an abstract procedural disagreement. The city has experienced the consequences of development decisions that affect water bodies, drainage channels and green spaces. The Supreme Court’s 2023 judgment, while dealing with a case concerning Chandigarh, referred to Bengaluru’s urban decline, including the September 2022 floods, water scarcity, traffic congestion, loss of lakes and encroachment of rajakaluves caused by unplanned development. The court said these concerns required the attention of lawmakers, the executive and policymakers.
The judgment also directed that a copy be sent to the Union Cabinet Secretary and the chief secretaries of all states for consideration. According to the report, the court’s observations were a broader recommendation to policymakers and did not create a blanket EIA requirement for every urban project under the existing notification. That distinction prevents the judgment from being treated as an automatic legal mandate for the tunnel road. It does, however, place the project within a wider policy debate about whether urban infrastructure should be evaluated only through project categories or also through the ecological systems it may affect.
The central evidence available so far is limited but consequential. There is a proposed 16.7-kilometre tunnel road. KSPCB has not received an EIA or REIA for it. The Board also has no internal assessment, inspection note, technical evaluation or correspondence concerning the ecological impact of excavation on Lalbagh’s flora, fauna and groundwater table. B-SMILE says the relevant assessments will be prepared under the Environmental Management Plan after the project is awarded and the final design is ready. These facts describe the current documentary position without proving either environmental safety or environmental damage.
The absence of a prior EIA also exposes the limits of category-based environmental regulation in large cities. Formal notifications provide a threshold for approvals, but urban ecological risk can arise from projects that are not traditionally treated as standalone environmental developments. A tunnel is primarily presented as a mobility intervention. Its potential effects, however, can extend to excavation spoil, groundwater conditions, construction staging, surface-level access structures and nearby green infrastructure. The evidence supplied in the RTI response does not quantify any of these impacts, which is precisely why the absence of baseline assessment is significant.
The policy landscape is consequently divided between mandatory approval and responsible planning. B-SMILE’s position is that the project will obtain necessary approvals under its Environmental Management Plan at the appropriate stage. The position expressed by the applicant and cited by mobility expert and environmentalist Sandeep Anirudhan is that sensitive green patches and groundwater reserves warrant environmental assessment before the project progresses further, even if the law does not expressly require a prior EIA.
Anirudhan linked that argument to the Supreme Court’s discussion of Bengaluru’s urban decline. He said the principle of assessing environmental impacts should apply to projects such as the tunnel road even when an EIA is not legally mandatory. His view is an expert argument, not a finding in the RTI response or a judicial order specifically requiring an assessment for this project.
That distinction should guide the next stage of public scrutiny. The immediate question is not whether the tunnel road should be labelled safe or unsafe on the basis of one RTI response. It is whether the project’s environmental management process will produce a transparent, technically credible record before construction decisions become difficult to alter. The supplied material does not establish the project award date, the final alignment, the location of construction shafts, the methodology for assessing groundwater or the timetable for approvals. Those details will determine how meaningful any later assessment can be.
The bigger urban question is whether Bengaluru’s infrastructure system treats environmental review as an approval hurdle or as part of project design. For a tunnel road, the most important risks may not be visible in the finished road. They may emerge during excavation or through changes to underground water conditions and surface ecological assets. Without baseline information, later monitoring has less capacity to identify what changed and why.
The RTI response confirms a gap in the KSPCB’s records, while B-SMILE says the environmental process belongs to a later project stage. What remains unresolved is how the final design will address Lalbagh and other sensitive ecological assets, what studies will be commissioned, which agencies will review them and when those documents will be made available. Those milestones will determine whether the tunnel road proceeds with an evidence-based environmental record or with safeguards disclosed only after key project decisions have already been taken.
