Over the past two decades, tunnelling in India has undergone a remarkable transformation, with a significant shift in techniques, scale, and capabilities. From the challenging terrains of the Himalayas to the dense urban centres, India has successfully tackled some of the most difficult tunnelling challenges, transforming connectivity across metros, highways, and rail networks. As the nation pushes forward with mega projects, tunnelling is increasingly seen as an integral part of India's infrastructure growth, with technology, safety standards, and efficiency improving year on year.

India’s tunnelling capabilities have significantly evolved, transitioning from traditional methods like drill-and-blast to more advanced techniques, including Tunnel Boring Machines (TBMs). Lt. Gen. Rajeev Chaudhary, former Director General, Border Roads Organisation (BRO), stresses the importance of these advancements in India’s growing tunnelling industry: “In the past, the majority of tunnels in India were built using drill-and-blast techniques. Today, we have transitioned to TBMs, which have revolutionised the speed and efficiency of tunnel construction.” The adoption of TBMs has brought about a paradigm shift in the way tunnels are constructed, reducing the time taken for excavation, increasing safety, and improving precision.

TBMs are particularly effective in challenging geological conditions, especially in urban areas, where traditional methods may be too dangerous or inefficient. India’s transition to TBM technology signifies a leap in tunnelling capabilities, reducing reliance on foreign technology and promoting domestic manufacturing of these machines. Lt. Gen. Chaudhary further adds, “We are now manufacturing TBMs domestically, a significant step towards self-sufficiency and a major breakthrough for the Indian tunnelling sector."

One of the most significant advances in India’s tunnelling sector is the construction of high-altitude tunnels. The country now boasts some of the highest tunnels in the world, such as the Atal Tunnel and the Sela Tunnel. The Atal Tunnel (the longest tunnel above 10,000 feet) and the Sela Tunnel (the longest twin-tube tunnel above 13,000 feet) stand as landmarks in the global tunnelling community. These projects have proven India’s ability to tackle some of the world’s most difficult tunnelling challenges at high altitudes.

India’s focus on high-altitude tunnelling is transforming the nation’s infrastructure capabilities. Lt. Gen. Chaudhary proudly states, “India has emerged as a global leader in tunnelling, especially in high-altitude regions. We are now building some of the highest tunnels in the world, and we no longer look up to the West for inspiration.”

Amberg Engineering has been at the forefront of providing advanced tunnelling solutions to India. Barad Sharma, CEO, Amberg Engineering, reflects on the rapid expansion of India’s tunnel network and the company’s increasing involvement in the country. “Since our registration in 2012, Amberg Engineering has established a solid presence in India, contributing to landmark infrastructure projects in metro, highways, railways, and hydropower. To further deepen our engagement, we’ve opened a new office in Mumbai and launched the Amberg Experience Centre in Gurugram, which showcases our full range of capabilities and serves as a platform for knowledge sharing and collaboration,” Sharma shares.

India presents significant challenges for advanced tunnelling solutions, including complex geological conditions, a price-sensitive market, and dense urban environments. Yet, Sharma sees substantial opportunities for innovation in the sector: “The Indian market’s scale, the government’s investment in metro, highways, and rail projects, and the growing demand for safer, smarter tunnelling solutions all create a strong growth potential for us,” he adds.

Amberg Engineering’s focus on cutting-edge technologies, such as Tunnel Seismic Prediction (TSP) and predictive maintenance, aligns with global trends in sustainable infrastructure development. “We integrate innovations like AI-driven analytics, BIM, and IoT-enabled sensors into tunnelling equipment to support real-time monitoring and data-driven decision-making,” explains Sharma. These innovations are improving safety, efficiency, and precision in tunnelling, ensuring that Amberg stays ahead of the curve in India's competitive market.

Overcoming challenges

Tunnelling through the rugged terrains of the Himalayas presents unique challenges, not just in terms of geology but also in logistics and safety. Brig Gurjeet Singh Kambo, Head – Special Initiatives, TI IC, L&T, shares his experience working on the Zoji-la Tunnel, a 14-km tunnel in Jammu and Kashmir, which is one of the most ambitious projects in India. “The Zoji-la Tunnel aims to connect Jammu and Kashmir with Ladakh. The challenges we face here are multi-dimensional—ranging from geological issues like soft and unstable strata to extreme weather conditions and security threats,” Brig Kambo explains.

Tunnelling in the Himalayan region is particularly complex because of the tectonic activity in these areas. “The geology is constantly changing due to shifting tectonic plates, and this results in unexpected water ingress, which poses significant risks during construction,” Brig Kambo notes. Despite these challenges, the use of advanced techniques, such as the New Austrian Tunnelling Method (NATM), has helped mitigate risks. NATM allows for real-time adjustments to the design as tunnelling progresses, ensuring that the tunnel’s structural integrity is maintained, even as geological conditions change.

Coastal and urban tunnelling

While high-altitude tunnelling presents unique challenges, coastal and urban tunnelling projects face their own set of difficulties, particularly related to water ingress and existing infrastructure constraints. Animesh Sharma, Assistant Manager – Civil, National High-Speed Rail Corporation (NHSRCL), provides insights into the complexities involved in tunnelling under coastal regions, specifically for the Mumbai-Ahmedabad High-Speed Rail Project, where tunnelling will pass under the Thane Creek. “Water ingress is a significant concern when tunnelling in coastal areas. We rely on advanced TBMs like the Earth Pressure Balance (EPB) machines, which help control groundwater seepage and maintain tunnel stability,” Sharma explains.

The challenges of tunnelling in coastal areas are compounded by the need to safeguard the environment and adhere to environmental regulations. “We must also consider the impact of tunnelling on marine life in coastal areas, especially with the growing concerns around climate change,” Animesh adds. This highlights the importance of sustainable tunnelling practices and a commitment to environmental responsibility.

Urban tunnelling also presents significant challenges, especially in densely populated cities like Kolkata, where the geology is soft and the city’s infrastructure is old. Animesh further elaborates, “In Kolkata, the density of buildings and limited space for machinery make tunnelling a logistical nightmare. We face issues like subsidence, and the proximity of existing infrastructure makes the situation even more complex.” However, the adoption of Building Information Modelling (BIM) and 3D geological modelling is helping to optimise tunnel design, reducing risks and improving construction efficiency.

Breakthrough innovations

India’s tunnelling sector is embracing breakthrough innovations that are reshaping the industry. Sanjoy Sanyal, Founder and Managing Director, Bouw Consultants, highlights the adoption of large-diameter TBMs in urban sectors, particularly in projects like the Mumbai Coastal Road Project, Mumbai Metro, and Delhi Metro. “India has successfully adopted large-diameter TBMs, some with diameters as large as 13.1 m, which are being used in difficult ground conditions in urban areas,” says Sanyal. These large-diameter TBMs enable efficient tunnelling in tight spaces and complex geological conditions, reducing excavation time and improving overall safety.

The integration of digital tunnelling and BIM is another key innovation that is transforming tunnelling practices in India. Azhar Jamil, Design Engineer Tunnel (Geologist), AECOM, explains, “In projects like NEOM (Saudi Arabia’s Smart City), we use high-resolution LiDAR, drone-based photogrammetry, and geophysical methods to develop 3D geological models that simulate subsurface behaviour.” These digital models feed directly into BIM systems, enabling real-time design optimisation and allowing for seamless collaboration among different stakeholders. “The integration of IoT sensors for real-time monitoring, alongside 3D geological modelling, helps manage risk and enhance the safety of tunnel construction,” Jamil adds.

Amberg Engineering continues to lead the charge in integrating cutting-edge technologies into India’s tunnelling solutions. “We adopt a data-driven approach to equipment selection, involving comprehensive geological and geotechnical analysis. This allows us to leverage BIM-supported simulations, risk modelling, and cost-benefit assessments to match tunnelling methods with specific ground conditions,” shares Sharma of Amberg. The company also utilises digital twin technology for continuous tunnel monitoring and asset management, aligning with global trends in smart infrastructure development.

“By using TSP, we can identify potential hazards before they occur, reducing risk and ensuring safer tunnelling,” Sharma explains. This technology, alongside automated real-time monitoring systems, is revolutionising the way tunnels are constructed, providing greater accuracy and safety in the process.

Water ingress: A challenge

Water ingress continues to be one of the most significant issues in tunnelling, particularly in areas with high groundwater levels, such as coastal regions and high-altitude tunnels. Brig Kambo discusses strategies employed to manage water ingress in the Zoji-la Tunnel, where water flow and the potential for flooding posed significant risks. “In Zoji-la, we had to contend with both entrapped and flowing water. Using NATM, we installed drainage systems to divert water into porous pipes, which helped prevent flooding within the tunnel,” he explains.

Advanced TBMs, such as slurry-type machines, are equipped to manage water ingress by creating a pressurised environment within the tunnel. Sharma adds, “We use slurry-type TBMs, which help control water ingress by creating a pressurised environment inside the tunnel. This significantly reduces the risk of water damage and ensures the stability of the tunnel structure."

Policy reforms

Despite the advances in technology, there remain significant challenges in the planning and execution of tunnel projects in India. Lt. Gen. Chaudhary stresses the need for better planning and regulatory reforms. "The lack of detailed geological surveys during the planning stage often leads to delays and cost overruns. We need to invest more in research and detailed site assessments before starting major tunnel projects,” he suggests. This highlights the importance of early-stage planning and the need for more rigorous geological surveys to ensure the success of tunnelling projects.

Amberg’s workforce development approach is also playing a pivotal role in India’s tunnelling success. “We support the development of our workforce through structured training programs, technical workshops, and mentoring, ensuring that engineers stay updated with the latest methods and innovations in the underground industry,” says Sharma. The company also collaborates with local academic institutions to build capacity in tunnelling methods and safety practices.

Sustainability and innovation

Looking ahead, the future of tunnelling in India is bright, with a growing emphasis on sustainability and innovation. Dheeraj Kumar Arora, Proprietor, SARAJ Drilling Solutions, highlights the role of sustainability in tunnelling technologies: "The integration of IoT, automation, and electrification in tunnelling equipment is crucial for reducing environmental impact. We need to ensure that future tunnelling projects are not just efficient but also environmentally responsible."

Brig Kambo underscores the importance of incorporating advanced safety features into tunnel designs, such as automated firefighting systems and ventilation control. "Sustainability is no longer optional; it must be a core component of all future tunnel projects," he concludes.

India’s tunnelling industry is on the cusp of a new era, marked by technological advancements, innovative techniques, and a growing emphasis on sustainability. From overcoming the challenges of high-altitude and coastal tunnelling to adopting cutting-edge TBM technology and digital tools, India has proven itself as a global leader in the tunnelling sector. With ongoing projects such as the Mumbai Metro Phase 4, Udhampur–Srinagar–Baramulla Rail Link, and others, India is poised to continue its leadership role in the global tunnelling landscape, setting new standards for innovation, safety, and sustainability.

As Sharma concludes, “The future of tunnelling in India is promising, and we are excited to continue our role in advancing tunnelling technologies and solutions to meet the growing needs of the country’s infrastructure.