"Sink the idea": Mumbai sweats over a sea plan that intitially made waves but is now causing ripples of worry

As Mumbai prepares to take advertising beyond its shoreline and into the Arabian Sea, the city risks extending its growing light pollution problem into marine habitats where darkness is essential for the survival of life, The Times of India reported on October 27.

The Maharashtra Maritime Board (MMB) is preparing to introduce floating digital billboards at coastal locations in Mumbai, triggering concerns about the plan's potential impact on marine ecosystems, ToI's report (by Joeanna Rebello Fernandes) said.

The board has identified 20 locations, including Juhu Beach, Lotus Jetty at Worli and Bandra Sea Link Jetty, for shore-based and floating advertisements.


The move comes seven years after New York banned floating digital billboards on its rivers, citing public nuisance and safety hazards.

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In Mumbai, the proposed installations could intensify artificial illumination along the coast, adding to an environmental problem whose effects on marine life are only beginning to receive greater scientific attention.

Light pollution is already recognised as a global environmental and public health concern. Research has linked artificial light to sleep disturbances, mood disorders and higher risks of obesity and cardiovascular diseases in humans. It can also alter plant growth and interfere with animals' natural behaviour and ecological relationships.

A landmark study by the UK-based Plymouth Marine Laboratory and University of Plymouth found that about 22% of the world's coastal waters are consistently exposed to artificial light at night. Sources include streetlights, fishing vessels and oil rigs. White and blue-rich LED lighting can penetrate up to 40 metres into the water, disturbing organisms adapted to darkness.

According to Minu Agarwal, assistant professor at CEPT University and founding member of DarkSky India, artificial illumination could interfere with the daily vertical migration of zooplankton.

Many species remain in deeper waters during daylight and move towards the surface after sunset to feed. This movement, among the largest migrations of living organisms on Earth, influences feeding patterns, predator avoidance and the transfer of energy through marine food webs.

In India, research on marine light pollution has largely examined illegal LED fishing, which uses artificial illumination to attract organisms towards fishing nets and disrupts natural feeding and migration patterns. Studies have also documented how artificial lights can disorient Olive Ridley turtle hatchlings, drawing them inland instead of towards the sea.

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An Olive Ridley turtle sighting at Juhu Beach last year raised hopes of their return but also highlighted the loss of ancestral nesting grounds to crowded and brightly illuminated beaches.

India's commitments under the Convention on the Conservation of Migratory Species of Wild Animals add to the need for safeguards.

India should follow the convention's guidelines to protect migratory wildlife, Shweta Kulkarni, a dark sky strategist working with the Maharashtra government on a dark sky policy, told ToI.

A resolution on light pollution affecting migratory species, including marine turtles and seabirds, was endorsed at the convention's Conference of the Parties in Gandhinagar in 2020. Formalised in 2024, the guidelines recommended a 20-km light-free buffer around important wildlife habitats and environmental impact assessments for proposed illuminated sites.

Mumbai's coastal waters are already under pressure. Vishal Bhave, assistant director for marine conservation at Srushti Conservation Foundation, said satellite monitoring showed that nearshore waters exceeded the threshold of 1.2 nanoWatts/sr/cm² used to distinguish pristine marine habitats, placing them in chronic pollution zones.

Floating billboards could introduce concentrated, high-intensity light at the waterline and eliminate naturally dark corridors.

Alternative ways of doing this are possible, ToI's report said. Mathi Thumilan, co-founder of Wild and Dark Earth, recommended using warm-spectrum lighting instead of blue-rich light, limiting brightness and installing timers to reduce illumination after active hours.

However, he argued that prevention was preferable to managing pollution after it became widespread. With commercial billboards offering big revenue opportunities, Thumilan warned that their numbers could grow well beyond the initial plan.