New Delhi: In the bustling northern outskirts of Jakarta, homes that once stood tall are now almost knee-deep in the earth. Over the past two decades, buildings have gradually sunk, streets have become flood-prone and landmarks have disappeared beneath rising waters. Residents remember mosques and ports that no longer exist – swallowed by the sea as land gives way.
This disturbing reality is not only Jakarta’s story. It is emerging as a silent catastrophe across many of the world’s rapidly growing cities – including several in India.
A recent international study conducted by Nanyang Technological University (NTU) in Singapore highlights an alarming trend: 48 major coastal cities around the world, including Kolkata, Chennai, Ahmedabad, Mumbai and Surat, are gradually sinking. The primary driver is not only rising sea levels due to climate change, but something more local and human-made – the overextraction of groundwater.
India’s Sinking Cities
Kolkata is experiencing land subsidence at rates ranging from 0.01 cm to 2.8 cm per year. Nearly 9 million people live in the affected areas. In places like Bhatpara, the land is sinking as much as 2.6 cm annually. Experts attribute this to the rampant withdrawal of groundwater – a common practice in overpopulated urban zones with limited water infrastructure.
The threat is not limited to erosion or flooding. Subsiding land also increases the city’s vulnerability to earthquakes and severe weather events, making disaster management a growing concern.
In Chennai, the situation is similar, with some parts of the city, particularly areas like Tharamani, sinking up to 3.7 cm annually. Here, around 1.4 million people live in regions facing gradual land loss. The cause, again, is excessive groundwater use, particularly for agriculture and industry, compounded by poor water management.
The most concerning figures come from Ahmedabad, where land in some neighborhoods like Piplaj is sinking at a rate of 4.2 cm per year, with some areas reporting up to 5.1 cm annually. Over 5 million residents are affected. The local government has initiated a Climate Resilient City Action Plan to mitigate the impact, focusing on solutions such as rainwater harvesting and artificial recharge of groundwater.
A Widening Global Crisis
The NTU study, supported by United Nations data, reveals that 160 million people across the globe are living in areas that are gradually subsiding – many of them in Asian cities built on river deltas or soft sediment.
These locations are especially vulnerable due to high population density and intense urban development.
Jakarta is now so low-lying that nearly half the city is below sea level. Thirteen rivers run through it, and worsening rainfall patterns are causing increasingly frequent floods.
Land in some parts of the city has sunk by up to four meters since the 1970s. The situation is so critical that Indonesia is now developing a new capital, Nusantara, to escape the environmental collapse.
Solutions and Warnings
Some cities have responded with visible defences – building sea walls, dikes and flood barriers. But these measures, while helpful, can sometimes backfire. When natural drainage is blocked, rainwater and river flows get trapped behind man-made structures – creating what experts call a “bowl effect”, worsening floods instead of preventing them.
Cities like Ho Chi Minh City, Alexandria and Jakarta have already built such barriers. However, the real long-term solution lies deeper – in managing groundwater responsibly.
Japan’s capital, Tokyo, faced a similar crisis in the 20th century. But by the 1970s, the city imposed strict regulations on groundwater extraction and implemented a robust water supply system.
This drastically slowed land subsidence, turning Tokyo into a global model for how science-based policy can reverse environmental damage.
