Tunnels have emerged as a key component of India’s infrastructure landscape. Tunnel construction activity has witnessed notable growth over the years, supporting both connectivity requirements and utility networks. The sector is witnessing a transformation with the adoption of advanced construction techniques, modern equipment and digital technologies. Sustainability is also emerging as a key focus area. Developments in these areas are enhancing safety, improving efficiency in construction and facilitating better project execution.
India’s growing tunnel construction activities are being driven by a range of infrastructure and connectivity factors. Government initiatives aimed at strengthening transport infrastructure and enhancing regional connectivity have notably increased tunnelling needs across the country. Particularly, demands for better connectivity in areas of complex terrain and the Himalayan regions have pushed for the construction of road and rail tunnels as a reliable all-weather and year-round solution. Moreover, rising urbanisation and limited availability of land in urban areas are pushing structures underground. This is further propelled by the expansion of underground metro and urban rail networks, which are other key drivers of tunnelling. In addition, with the growing need for energy storage, tunnels are serving an important role in hydro projects.
Key emerging trends
Advances in tunnelling techniques
Tunnelling techniques adopted across projects are witnessing a gradual move towards methods that are better suited to varying ground conditions. Over the years, tunnel construction has seen the use of various methods of tunnel excavation and tunnel support, decided based on factors including geological conditions, on-ground characteristics and dimensions of the tunnel, among others. Previously, conventional methods included the use of the drill-and-blast method or the cut-and-cover method for excavation, followed by providing primary support for the tunnel based on ground conditions. While these techniques continue to be used in a sizeable number of projects, newer and more mechanised techniques and advanced methods, including the New Austrian Tunnelling Method (NATM) and tunnelling using tunnel boring machines (TBMs), are seeing greater deployment. These approaches have improved construction speeds and reliability.
The NATM involves the continuous monitoring of ground conditions and providing support to the tunnel perimeter using the surrounding rock mass and shotcrete, anchors and other tools. This technique is now being widely deployed for tunnelling projects in the Himalayan region. The complex geology and varying ground conditions make the NATM particularly well suited for tunnelling in the region, with key projects including the Sonamarg tunnel and the Sela tunnel in the region having been built using NATM.
In addition, the use of TBMs is emerging as a key trend in the sector, particularly for urban tunnelling projects. Their ability to operate with lower vibrations, noise and on-ground impacts makes them suitable for tunnelling beneath dense urban settlements. They also facilitate faster and continuous excavation, enhanced safety and precision and offer a consistent profile. Moreover, the widespread application of TBMs in underground metro rail projects has emerged as a significant trend. Recently, the Patna metro rail project witnessed the breakthrough of the seventh TBM. Further, breakthroughs were achieved at the Thirumayilai shaft and at the Mandaveli station under Phase II of the Chennai Metro Rail Project in February 2026.
Rising integration of technology and digitalisation
The tunnelling segment is increasingly leveraging advanced technologies and digital solutions across various stages in the life cycle, from project planning and investigation to construction, operations post-completion and maintenance. These include the use of advanced tools such as building information modelling, artificial intelligence, internet of things, drones, smart mapping systems, automation and real-time monitoring systems, in addition to tools such as ground penetrating radar and tunnel seismic prediction. The adoption of such technologies during the initial stages of the project is enabling a more comprehensive understanding of geological characteristics. This is, in turn, facilitating better identification of weak zones, water-bearing strata and potential geological hazards, thereby enhancing project management and enabling informed decision-making. It is also facilitating the transition towards predictive and preventive maintenance of tunnel assets and equipment, helping improve operational reliability and reduce costs. The Mumbai-Ahmedabad High Speed Rail Project, for example, features the use of various monitoring instruments to facilitate safe tunnel excavation while preserving surrounding infrastructure. These include surface settlement points, optical displacement sensors or tilt meters, BRT (by-reflect target/3D targets), and seismographs to monitor vibrations and seismic waves.
Enhanced focus on safety and monitoring
Safety has become a key consideration across the tunnel life cycle. Measures are being incorporated right from the initial construction stages, given that tunnel incidents can be more hazardous than those associated with surface construction. Growing emphasis is now being placed on comprehensive risk assessment, detailed groundwater surveys, geological investigations, comprehensive data collection and enhanced geological mapping. Risk and safety aspects are also being integrated during the tendering stage.
During construction processes, safety is being strengthened through automated and remote drilling and blasting techniques, continuous monitoring of work and workforce, regular safety inspections, effective communication systems and real-time incident reporting. Moreover, tunnel designs are also evolving to prioritise safety features such as escape tunnels and emergency exits. The Thane-Borivali twin tunnel, for example, features a dedicated emergency lane, with cross-passages every 300 metres.
Various fire safety and mitigation measures are also being incorporated both at the construction and operations stages. These include enhanced ventilation systems, the use of fire-resistant materials and water mist fire suppression systems. Moreover, ventilation provisions are also being decided based on tunnel length and operational requirements. During operations in the tunnel post construction, effective ventilation systems are aiding in removing pollutants and maintaining air quality, while elements including displays, information systems, telephone booths, emergency exits and other safety infrastructure are aiding in ensuring smooth operations and effective emergency response. For instance, the Mumbai-Ahmedabad High Speed Rail Project is set to feature the use of a tunnel hood technology that will address changes in air pressure that take place when trains enter tunnels at high speeds. This is aimed to reduce noise generated by trains and reduce negative impacts to surrounding communities. In another notable example, Tunnel T50 under the Udhampur-Srinagar-Baramulla Rail Link Project features CCTV cameras placed every 50 metres and a parallel escape tunnel linked every 375 metres for safety.
Adoption of sustainable initiatives gains traction
Tunnel projects are now prioritising sustainability measures and reducing the carbon footprint in line with broader net zero goals. There is a growing emphasis on minimising surface-level impacts, especially in ecologically sensitive areas. These are also being guided by environmental directives to ensure minimal disruptions to these areas. For example, the Thane-Borivali twin tunnel, spanning over 11 km, passes beneath the Sanjay Gandhi National Park. The project is being excavated using TBMs to facilitate safe excavation and ensure minimal ground disruption.
In addition, project developers are also focusing on the effective disposal and reuse of excavated muck. This includes identifying opportunities for its reuse both within the project and for other construction applications. Moreover, the use of energy-efficient systems and equipment is also gaining traction, improving resource efficiency.
Other trends
There is a growing focus on the indigenisation of tunnelling equipment and technologies. This is aimed at reducing dependence on imports and strengthening domestic capabilities. Moreover, the adoption of new materials and advanced equipment for tunnel construction is also contributing to improved construction efficiency, safety and overall project performance.
Projects are also placing greater emphasis on comprehensive pre-construction investigations, including detailed geological and geotechnical surveys. A better understanding of ground and rock conditions is facilitating the adoption of tunnelling methods that are best suited to the geology.
Challenges
Despite notable advancements in tunnelling technologies and practices over the years, challenges continue to loom. Geological complexities stand as a key challenge, especially in the Himalayan region and areas of uncertain terrain. These are characterised by heterogeneous rock formations, squeezing ground conditions, water ingress, stress-induced rock bursts, collapses and cavity formations. These pose significant safety risks and affect the pace of project execution. Other issues include challenges in approvals and clearances, high project costs, shortages of skilled labour and the need for better risk-sharing mechanisms between project stakeholders. Further, delayed retrieval of TBMs, particularly when they are scheduled for redeployment on other stretches, can lead to delays.
While such challenges are often unavoidable, the adoption of advanced investigation technologies, monitoring systems and modern tunnelling techniques is helping to mitigate their impact.
Outlook
Looking ahead, India sees notable opportunities in the tunnelling segment, with various connectivity and utility projects planned in the coming years. The demand for TBMs is expected to see an upward trend, supported by the strong pipeline of planned metro rail projects. This also creates opportunities for domestic manufacturing and strengthening indigenous capabilities. Moreover, the focus on safety is expected to remain, being embedded as an integral part of the project rather than as an additional component. While challenges exist, continued innovation and stronger stakeholder collaboration are expected to drive the sector forward.
