Singapore, a nation that has time and again proven that it is ahead of its time, is yet again at the forefront of urban innovation as it seeks to alter city life as we know it. As successful as the city-state is in economic, social, and political terms, Singapore is running out of land to build on, leaving officials scrambling to find a solution to diminishing land. During this year’s World Urban Forum 9 (WUF9) in Kuala Lumpur, Singaporean mining engineers spoke about one of Singapore’s biggest mining projects in recent years: underground expansion of urban space.

It is no surprise that Singapore is looking to expand underground due to the country’s small size, which is a mere 719.9 km2 (447 miles), making it 11,106 times smaller than Australia. With the majority of its land in commercial or residential use, the city is struggling to provide housing for its growing population, which will near 6.9 million by 2030. As part of the master plan for Singapore’s development, the city-state plans on investing $188 million in research and development to follow what is known as the underground urbanism movement, a movement towards underground expansion rather than overground.

Underground urbanism can be anything from developing metro systems, which is the movement in its most common form, to artificial reservoirs and entire underground malls. In Singapore’s case, the island city-state is looking to use subterranean land for storing anything from data centers and wine to cars. When the idea first came to fruition, there were legal challenges to seizing underground land, since land underneath residences and stores are technically considered private property.

In order to facilitate the excavation of land below the surface, in 2015, the government amended a land law in that declared land 30 meters below private property as state property, and another that allows the state to purchase surface land to excavate beneath it. Singapore finished construction of the Jurong Rock Caverns nearly three years ago, which serve as the island’s first underground storage for liquid hydrocarbons like crude oil. Following suit, the city built a 37 kilometer (23 mile) long tunnel system to transport goods across the city as to avoid utilizing surface land in the face of growing urban density and shrinking land mass.

underground expansion

Some of the ideas being explored for Singapore’s underground expansion. (Courtesy of Straits Times)

Singapore was honored last year at the International Tunneling Association Awards for its plans for underground expansion; Hong Kong was previously honored at the same awards for its underground real estate caverns in 2016. Singapore and Hong Kong, however, are not the first cities to consider looking underground to expand urban space. And while the two cities are doing so to find alternatives to shrinking space above ground, other attempts to develop underground have highlighted a number of other benefits to the expansion.

Montreal has one of the world’s first underground cities, known as RECO, which has an impressive 32 kilometers (almost 20 miles) worth of tunnels, and acts as shelter from the harsh Quebecois winters. Finland has pursued underground expansion to curb urban sprawl since as early as the 1960s, also developing a city underground, which doubles as a training ground for the country’s army, and includes a church and heated swimming pools.

Aside from attempts to fight pollution and harsh weather conditions, countries like Turkey look to expand underground to curb traffic congestion. The Turkish Republic unveiled plans to build a triple decker tunnel that crosses beneath the Bosphorus Strait in order to alleviate pressure on Istanbul’s other bridges. In 2016, New York City revealed its plans to build the world’s first subterranean public park to repurpose unused space in the city.

As innovative as Singapore’s move to utilize its underground space is, the move has garnered some grounded criticism. The biggest fear from pushing urban expansion underground is the risk that comes with placing people scores of meters below the ground. Urban expansion underground has large potential for stimulating claustrophobia and fear among people spending elongated periods of time underground. Scandinavia has laws in place requiring employers to allow workers to go above ground for breaks at 30-minute intervals. There is also the fear of underground flooding or other crises occurring, making seeking safety difficult.

Liu Thai Ker, Singapore’s former chief planner, is opposed to the underground expansion on grounds that many city dwellers will oppose the idea. “The big push for underground space is a cop-out,” Liu said, according to Cityscope. “If you are short of land,” Liu continues, “the solution is to find a better way to create a liveable environment above ground, at a higher density. In my book, going underground is not innovation.”