India’s infrastructure development has been a key driver of economic growth, with road tunnel construction playing a crucial role in improving connectivity across the country. With the rising demand for more efficient and reliable transportation networks, the focus on building robust road tunnels has also increased. These tunnels not only reduce travel time but also provide all-weather connectivity, especially in challenging terrain such as the Himalayan and north-eastern regions of India.
The expansion of the road tunnel network is being driven by a combination of factors, including the need for improved infrastructure in remote areas, the demand for better transportation links and the government’s emphasis on sustainable development. Furthermore, major tunnelling projects such as the Atal Tunnel and the Chenani-Nashri Tunnel have set new benchmarks in engineering skills and project execution.
Current construction trends
India’s road tunnel sector is experiencing significant development, particularly in the northern and north-eastern regions, which are characterised by challenging mountainous terrain. Historically, these regions have been underdeveloped in terms of infrastructure, with limited connectivity and access. The ongoing construction of road tunnels in these areas is aimed at providing all-weather access to remote locations, facilitating economic growth and improving the quality of life for local communities.
Key projects such as the Atal Tunnel, the world’s longest highway tunnel above 10,000 feet, provide year-round connectivity between Manali and the Lahaul-Spiti valley in Himachal Pradesh. Similarly, the Chenani-Nashri Tunnel, India’s longest road tunnel, has significantly reduced travel time between Jammu and Srinagar, while the Sela Pass Tunnel in Arunachal Pradesh has improved connectivity to the Tawang region.
Key upcoming tunnels
In recent years, India has made significant strides in the road tunnelling sector, with several ambitious projects transforming connectivity across difficult terrains. The Zojila Pass Tunnel in Jammu & Kashmir is set to become one of Asia’s longest bidirectional road tunnels upon completion, ensuring year-round connectivity between Srinagar, Kargil and Leh. This project will significantly reduce travel time in this snow-prone region, highlighting the crucial role of road tunnels in overcoming environmental challenges. The project is being executed by Megha Engineering and Infrastructure Limited (MEIL) at an estimated cost of Rs 68 billion. As of August 2024, over 50 per cent of the construction work is completed, with the project expected to be finished by 2026.
Similarly, the Goregaon-Mulund Link Road Tunnel Project (GMLR), being executed by J. Kumar Infraprojects Limited, spans 6.3 km and will provide faster routes across the city’s hilly terrain, significantly reducing travel time between eastern and western Mumbai. In July 2024, the central government laid the foundation stone for the third phase of the project.
Further, the proposed BBMP Tunnel Project in Bengaluru, announced in June 2024, is an 18 km tunnel road connecting the Hebbal Esteem Mall Junction to the Central Silk Board Junction. It aims to alleviate traffic congestion in the city. A notable upcoming project in the sector is the Shinku La tunnel, connecting Manali and Leh via Darcha-Padun-Nimmu. With construction expected to begin by September 2024, this 4.1 km tunnel will be the world’s highest, located at an altitude of more than 16,600 feet.
Odisha’s first highway tunnel is also nearing completion and has set a new record for the National Highways Authority of India (NHAI) with an excavation of 750 metres in a month and a daily face excavation of 36.8 metres.
The government’s focus on infrastructure development has led to the speedy awarding of several large-scale tunnel projects. These include the Orange Gate-Marine Drive Underground Tunnel in Mumbai, the Versova-Dahisar Link Road (Mumbai Coastal Road Project Phase II, Package D) and the Kharghar-Turbhe Tunnel Road Project.
Tunnelling techniques
The expansion of road tunnels in India involves the use of different construction techniques such as the New Austrian Tunnelling Method (NATM) and tunnel boring machines (TBMs). Among these, TBM remains the dominant method. NATM is widely preferred in mountainous regions for its flexibility and cost-effectiveness. It leverages the surrounding rock’s natural strength for stability, making it adaptable to challenging geological conditions and areas prone to seismic activity, reducing the risk of collapse. Meanwhile, TBM is preferred for large-scale urban and long tunnel projects. It provides faster excavation with higher precision and safety, minimising disruptions on the surface and enhancing worker safety by providing a secure environment within the machine.
For instance, the Siliguri Sevoke Tunnel project in north-eastern India used a combination of NATM and TBM to address complex geological conditions, including frequent seismic activity. NATM’s adaptability to unstable rock formations allowed for continuous monitoring and adjustments in construction, while TBMs ensured efficient boring through longer stretches of the tunnel. Similarly, the 9.02 km Atal Tunnel in the Himalayas used the NATM approach due to its ability to adapt to the region’s challenging geological and seismic conditions.
Safety and sustainability
Modern tunnel projects in India are increasingly prioritising safety and sustainability through innovative technologies and eco-friendly practices. For instance, the Zojila Tunnel employs smart sensors for real-time monitoring of air quality, structural integrity and traffic flow, enabling quick responses to potential hazards. Similarly, the Eastern Peripheral Expressway tunnels use energy-efficient LED lighting, reducing power consumption while improving visibility for drivers. In the Mumbai Coastal Road Project, low-carbon concrete and recycled materials are used to minimise the environmental impact, along with stormwater management systems to protect surrounding ecosystems. These advancements not only improve the safety and efficiency of tunnel operations but also contribute to the development of sustainable infrastructure in India.
Upcoming tunnels
The completion timelines for ongoing road tunnel projects are key to assessing the sector’s current pace of development. According to India Infrastructure Research, as of May 2024, more than 210 tunnels spanning a total length of over 460 km are at various stages of development. Of these, over 100 tunnels spanning 150 km are under construction, and over 90 tunnels totalling a length of more than 250 km are in the planning stage.
As per India Infrastructure Research, a significant number of these road tunnels are expected to be completed between 2024 and 2028.
Furthermore, in September 2024, the Ministry of Road Transport and Highways (MoRTH) announced plans to construct 74 new tunnels, spanning 273 km, at an estimated cost of Rs 1 trillion. This initiative aims to enhance India’s highway infrastructure while ensuring stringent performance audits for all ongoing projects. Technology upgrades and cost-effective solutions will be prioritised to address India’s varied terrain while maintaining top quality standards.
So far, the central government has completed 35 tunnels covering 49 km at a cost of Rs 150 billion. In addition, 69 tunnels, stretching 134 km, are currently under construction with an estimated expenditure of Rs 400 billion.
The way forward
India’s road tunnelling sector faces significant challenges due to rugged terrain, seismic activity and extreme weather, particularly in the Himalayan and north-eastern regions. These factors drive up costs and complexity, as seen with the Rs 80 billion in the BBMP Tunnel in Bengaluru, and demand advanced engineering, skilled labour and strict environmental management. However, with substantial growth anticipated through government initiatives and increased connectivity demands, strategic investments in research and development, smart systems and sustainable practices are crucial. Strengthening public-private partnerships and enhancing workforce skills will be essential to overcoming these challenges, ensuring that India builds world-class infrastructure that promotes economic growth and improves road standards.