Bengaluru’s fully underground Inner Ring Metro proposed by IISc put on backburner

Bengaluru’s ambitious 34-km fully underground Metro line - Inner Ring Metro (IRM) – which was advocated by the Indian Institute of Science (IISc) to connect the city’s core areas has been effectively put on hold, after not finding mention in the official Namma Metro Phase 4 expansion plan.

The proposed IRM line was expected to ease traffic congestion in the city’s central districts, but has instead been overlooked even as the state government is planning to extend Metro corridors to Bengaluru's satellite towns.

The IRM's Origin

In 2020, the IISc submitted a preliminary demand assessment and technical evaluation report on the corridor to Bangalore Metro Rail Corporation Limited (BMRCL). The study, led by Ashish Verma of IISc’s civil engineering department assessed the viability of implementing the 34-km underground line using scientific data.

Also Read: Bengaluru traffic: IISc bats for Inner Ring underground Metro over DKS’ tunnel road plan

Following the IISc study, the corridor was included in the state’s Comprehensive Mobility Plan (CMP) 2020, which envisioned a 317-km metro connectivity network by 2031. The IRM was planned with 23 new stations and six interchanges, linking major commercial and educational hubs to decongest central Bengaluru.

“IRM line is proposed on busy corridors that are usually congested, providing better coverage for the city centre. Every location where the IRM line crosses other Metro lines has an interchange, ensuring seamless connectivity,” the IISc report said.

Priority to extensions in outskirts

The state government has instead asked BMRCL to prepare feasibility reports for routes to towns such as Tumakuru, Devanahalli, Harohalli, Attibele, Bidadi, Tavarekere, Hoskote and Jigani. No feasibility study has been conducted for the IRM so far, even though experts suggest the Metro should first strengthen connectivity within the city of Bengaluru, while suburban rail can focus on the outskirts.

Also Read: Bengaluru's traffic conundrum: Metro rail to the outskirts, suburban rail confined to city limits, and tunnel vision

Financial and Engineering Challenges

BMRCL’s managing director J Ravishankar was unavailable for comment. One BMRCL official told Moneycontrol that a fully underground Inner Ring Metro would be expensive and technically challenging. “There are many factors - cost, depot location and several engineering and geographical hurdles unique to Bengaluru. The city’s varying elevations make it difficult to design a continuous underground line,” the official said.

“It is not that the project is being dropped permanently - it may be taken up later. But building any underground tunnel within the city is the biggest challenge, from land acquisition to property development. Underground construction is far from easy. Criss-crossing other lines requires deep tunnelling, which brings major technical and cost complications,” the official added.

This comes at a time when the state government is pushing the Tunnel Road project despite opposition from citizen groups.

Also Read: Bengaluru tunnel road: Govt expert panel flags DPR flaws, warns of cost escalation, Metro overlap

Prioritise Metro over Tunnel Road

IISc’s Ashish Verma, who led the study for the underground metro line has criticised the delay. “BMRCL hasn’t even initiated a feasibility study for the IRM yet. The government keeps talking about decongesting the city centre, but this line has the real potential to do so. Completing the Inner Ring would allow seamless transfers between multiple radial lines, enabling commuters to travel efficiently across the city. This would have a far greater impact on relieving congestion than projects like Tunnel Road, which claim to decongest but fail to provide real solutions,” Ashish Verma said.

The IISc professor believes the IRM is a sustainable project that can reduce travel time, but it is being ignored. “The government always asks for alternatives for tunnel road but does not listen to experts. The IRM is part of the Comprehensive Mobility Plan (CMP), yet BMRCL seems to be avoiding the project because the focus is on pushing the Tunnel Road project. The IRM line is a sustainable, long-term solution and would act as a crucial link, allowing seamless transfers between ring and radial lines so commuters can reach any point via the shortest route,” Verma said.

“In a city shaped like Bengaluru, a dense, spider-web-like MRT network with multiple radial and ring lines is essential. Yet while attention is given to routes to Tumakuru and other outskirts, the core city problem remains unsolved. The government is pushing unsustainable projects with little real impact on congestion,” Verma said.

Also Read: Bengaluru civic body under lens for alleged ‘copy-paste job’ in Rs 9.5 crore tunnel road DPR prepared by consultant

What the Study Says

According to the IISc study, adding the IRM to the Metro network by 2030 could increase overall Metro ridership by about 77 percent compared to the business-as-usual scenario. The total network, including the IRM, would span roughly 203 km, with maximum ridership projected between Whitefield and Ujjwal stations at 48,425 passengers per hour per direction (pphpd). The IRM line itself could see 33,016 pphpd between Hosahalli and Padarayanapura, and 24,477 pphpd between Sandal Soap Factory and IISc stations.

The study projected that vehicle kilometres travelled (VKT) could drop by nearly 14 percent if the 34-km IRM stretch with 13 interchanges are implemented due to a modal shift from private vehicles to Metro. While total CO₂ emissions would rise because of Metro’s energy use, per capita emissions would fall as commuters switch from cars and two-wheelers to public transport. Fuel consumption too is projected to fall by around 11 percent due if the IRM is adopted.

Also Read: Skeletons tumble out of Bengaluru tunnel road project reports, BBMP left red-faced

The IISc researchers baxked IRM to fill a critical gap in Bengaluru’s Metro network through a 'spider-web' structure combining radial and circular lines, allowing commuters to travel across the city without passing through Majestic, the current interchange hub.

“Providing a Metro network on high-density corridors with more round trips can make Metro an attractive mode of travel, reducing emissions and congestion while improving quality of life,” the report had said.

Also Read: DK Shivakumar: Bengaluru tunnel road project to take over four years, won’t affect Vidhana Soudha or Lalbagh