Why Mumbai is sinking? Study reveals Mumbai sinking at 2mm per year

Mumbai Sinking: Mumbai city is sinking at an average rate of 2mm per year because of a geographical phenomenon known as land subsidence, recent research done by the researchers of IIT Bombay has found. The experts have also warned that Mumbai is likely to see increased flooding unless urgent remedial action is taken by the urban planners and municipal authorities.

The study that claimed that Mumbai is sinking was published in the peer-reviewed Geophysical Research Letters journal in March. It analyzed the land subsidence in 99 countries globally and found that Tianjin in China is the fastest sinking coastal city in the world at a rate of 5.2 cm per year.

Mumbai Sinking: Why is it happening?

As per the research done by the researchers of IIT Bombay, Mumbai is sinking because of a geographical phenomenon known as land subsidence.

Land subsidence refers to the downward, vertical movement of the Earth’s surface which could be caused because of the groundwater extraction, mining, reclamation of natural wetlands, ecological disturbances, and infrastructure projects.

At least 33 cities are sinking by more than 1 cm a year. https://t.co/0rmA1ERCV7

— Big Think (@bigthink) May 31, 2022

Mumbai sinking: How researchers analyzed the sinking level of 99 coastal cities?

The methodology used by the researchers was first to collect the satellite images of 99 coastal cities that are captured (between October 2014 and January 2021) by the C-band Sentinel- 1 A/B Satellite, commissioned by the European Commission and the European Space Agency.

The images of 99 coastal cities were then analyzed using the Interferometric Synthetic Aperture Radar. It is a commonly used technique for measuring the deformations in the Earth’s surface through remote sensing.

The researchers, for each city, processed one satellite image every two months. A total of 6 images were analyzed every year for establishing the rate of land subsidence over a five-year period.

Mumbai Sinking 2mm: Which of the areas are sinking faster in Mumbai?

Other studies have shown that the Arabian Sea is rising by 0.5 to 3mm per year, suggesting that some parts of Mumbai city may be sinking faster than the sea levels are rising.

The highest subsidence was recorded in Churchgate, Colaba, Byculla, Kalba Devi, Kurla, Andheri East, Mulund, Dadar, Nahur East, Wadala, and parts of Tardeo, Trombay, Bhandup, and Govandi.

Another study conducted at IIT Bombay identified two major subsidence areas in Munbai0 Vasai and Wadala.

Mumbai Sinking: What can be done?

The Bombay Municipal Corporation (BMC) launched an ambitious Climate Action Plan earlier in 2022. As per the experts, the authorities are required to pay urgent attention to land subsidence as a scientific and socio-economic issue, as the areas that are prone to subsidence may experience the worst impacts of flooding and property damage.