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Urban Redevelopment Authority (URA)

An Underground of Possibilities

Read more about how Singapore explores underground spaces to optimise our limited land and build resilient urban infrastructure.

Last updated 4 June 2026

What underground spaces does Singapore have?

Linear infrastructure

Major infrastructure lines for rail, road, water, sewage and electricity are built underground to reduce negative impacts on the surface environment. Implementing Common Services Tunnels (CSTs) and Utility Specific Ducts (USDs) to consolidate multiple utilities saves space and provides spare capacity for future lines. Coordinating major underground utility and infrastructure works years in advance also helps to optimise the increasing usage of underground spaces.

Basement spaces

Shallower basements can house pedestrian links, retail spaces, car parks and utility facilities, while deeper basements can be utilised for MRT stations and water reclamation plants. We will do more to expand the types of uses in basement spaces by overcoming technical challenges such as fire safety.

Caverns

Built within deep rock to yield large underground spaces, caverns such as the Mandai Underground Ammunition Facility and Jurong Rock Caverns have been developed for storage.

Diagram of a utility tunnel, including utility specific ducts and common service tunnels.

Underground Ilustration

Diagram illustrating Singapore's use of underground space for infrastructure, transportation, and community amenities.

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Building resilience for the long haul

Seizing opportunities

There is great potential for our underground spaces. We will continue to explore innovative underground uses and ways to future-proof our existing infrastructure systems.

Isometric view of a city with underground tunnels for water and aggregate storage.

As we construct more underground structures, what other uses could we co-locate with them?

We have built major water management infrastructure underground, such as the Bidadari Underground Service Reservoir and Stamford Detention Tank. Could larger infrastructure, such as for water and energy, be located underground to free up more surface space?

We have constructed caverns such as the Mandai Underground Ammunition Facility and the Jurong Rock Caverns. We are also exploring the possibility of a cavern for construction aggregate storage at Gali Batu. Could caverns be designed to expand and adapt over time to house multiple uses?

We would like to hear what you think about going underground in Singapore!

Developing capabilities

We do not only build for today. The skills and expertise that we learn must be channelled into innovating and developing capabilities for the future. This helps us to be agile and responsive to evolving trends and land needs, such as those related to climate change.

Mapping what lies beneath

Harnessing technology to map underground spaces accurately ensures efficient space usage, minimises risks, and prevents disruptions to utility services.


Architectural rendering of the National Healthcare Group Polyclinics' waiting area. People seated and walking around the space.

Mapping our underground geology. (Source: BCA)

Full stadium view with fireworks. Fans fill the stands, teams line up on the green pitch.

3D map of as-built structures and piles.

White Peugeot van on a road with equipment attached to the back, likely for utility project use.

Source: HSC Pipeline Engineering Pte Ltd

Mapping underground cables and pipelines using advanced scanning technologies minimises the need for excavation and road closures.

Pushing technological boundaries

As new needs arise, we will keep pushing the boundaries of what can be put underground and how these spaces are constructed, operated and maintained.

Aerial view of Sembcorp battery energy storage system. Rows of containers on a gravel surface.

Source: Sembcorp

Feasibility studies could give rise to more underground uses. For example, studies are being carried out to determine whether Battery Energy Storage Systems (BESS) could operate safely underground, supporting our renewable energy efforts.

Abstract tunnel with orange wireframe trucks and blue grid lines.

Image was created with the assistance of AI for illustration purposes only.

Technological advancements in underground applications could offer solutions such as remote operations and monitoring of structural health in difficult-to-access areas.