The Maharashtra Maritime Board’s plan to introduce shore-based and floating billboards at 20 coastal locations in Mumbai is more than a new advertising proposal. It brings the city’s expanding commercial use of public and maritime spaces into direct contact with a less visible urban system: the darkness that marine organisms need to feed, migrate and avoid predators.
The locations identified by the board include Juhu Beach, Lotus Jetty at Worli and the Bandra Sea Link Jetty. The reported plan would extend Mumbai’s advertising market from roads, buildings and transport infrastructure into the Arabian Sea and the intertidal edge. That shift matters because artificial light at night is not confined to what humans see from the shore. Light from coastal infrastructure can enter the water column and alter biological processes that support marine food webs.
The proposal has been reported by the Times of India, which said the Maharashtra Maritime Board was clearing the decks for the billboards. The report does not establish that all 20 sites have received final environmental or operational clearance. It does, however, identify a planning direction that places commercial signage within a coastal environment already experiencing high levels of artificial illumination.
That distinction is important for Mumbai’s governance system. A billboard on land is generally assessed through questions of traffic visibility, structural safety, advertising regulation and public-space management. A floating or water-edge billboard adds other layers: maritime permissions, navigational safety, shoreline access, coastal ecology, lighting design and the effect of illumination on wildlife. The central administrative question is therefore not only who can sell advertising space, but how a revenue-generating use is evaluated when its effects cross from a regulated structure into a shared ecological system.
Light pollution is increasingly treated as an environmental and public-health concern. The report cites research showing links between excessive artificial light and poor sleep, mood disorders, obesity and cardiovascular risks in humans. In plants and animals, artificial illumination can alter growth, behaviour and ecological interactions. Coastal and marine impacts have received less public attention, but the evidence cited in the report points to a system in which darkness is an active environmental condition rather than an absence of development.
Research by the UK-based Plymouth Marine Laboratory and the University of Plymouth found that approximately 22% of the world’s coastal waters are consistently exposed to artificial light at night from sources including streetlights, fishing boats and oil rigs. According to Minu Agarwal, assistant professor at CEPT University and a founding member of Dark Sky India, light—particularly white or blue-rich LED light—can penetrate up to 40 metres into the water column.
The most important process affected may be the daily vertical migration of zooplankton. Many zooplankton species remain in deeper water during daylight and move towards the surface after sunset to feed under darkness. Agarwal described this movement as one of the largest migrations of living organisms on Earth. Artificial illumination can disturb where these organisms feed and how they avoid predators, potentially changing how energy moves through the marine food web.
This is not a marginal ecological process. Plankton occupy an early position in marine food chains, and changes in their movement can affect organisms that depend on them. The supplied report does not establish the precise impact that Mumbai’s proposed billboards would have on local species or on any particular food-web pathway. It does show why concentrated, high-intensity lighting at the waterline should not be treated as equivalent to an ordinary urban advertising display.
India’s existing experience with marine light pollution has largely involved illegal ‘LED fishing’. That practice uses artificial light to attract organisms towards fishing nets, creating an artificial food chain that can draw species from plankton to larger predators. Research has also examined the effect of artificial light on Olive Ridley turtles, whose hatchlings can be drawn inland towards urban illumination rather than towards the sea.
Mumbai’s own coastline provides a local warning. An Olive Ridley turtle sighting at Juhu Beach last year generated hopes of a wider return, while also highlighting the loss of ancestral nesting conditions to crowded and brightly lit beaches. The report does not claim that the proposed billboards would directly prevent turtle nesting. It does show that the city’s shoreline is already a contested environment in which lighting, recreation, commerce and wildlife movement overlap.
Shweta Kulkarni, a dark-sky strategist working with the Maharashtra government on a dark-sky policy, said India’s obligations as a signatory to the Convention on the Conservation of Migratory Species of Wild Animals require attention to the safe passage of migratory wildlife. A resolution on light-pollution guidelines for migratory wildlife, including marine turtles and seabirds, was endorsed at the Convention’s Conference of the Parties held in Gandhinagar in 2020. The guidelines were formalised four years later, according to the report.
Those guidelines recommend a 20-kilometre light-free buffer around important wildlife habitats and call for an environmental impact assessment of proposed illuminated sites. The available report does not specify whether any of the 20 coastal billboard locations falls within such a habitat or whether an assessment has been completed. That missing information is central to the public evaluation of the proposal. Without site-specific ecological assessments, the plan remains difficult to judge beyond its broad risk profile.
Mumbai already has a significant light burden along its coastline. Vishal Bhave, assistant director for marine conservation at Srushti Conservation Foundation, said satellite monitoring showed that Mumbai’s nearshore waters exceed the threshold of 1.2 nanoWatts per steradian per square centimetre used to delineate pristine marine habitats. He described the local waters as being in chronic pollution zones.
Bhave said floating commercial billboards would add concentrated, high-radiance beacons directly at the waterline and could erase remaining natural marine dark corridors. The phrase is significant from an urban-planning perspective. A dark corridor is not a visible road, park or transport route, but it performs a similar ecological function by allowing nocturnal movement and behaviour to continue without interruption. Mumbai’s planning frameworks often make physical infrastructure visible in maps and approvals; the effects of light require a different kind of spatial assessment.
The board’s proposed locations also show how the issue connects several types of public infrastructure. Juhu Beach is a heavily used public shoreline. Lotus Jetty at Worli and the Bandra Sea Link Jetty are linked to the city’s maritime and transport geography. Placing advertising at these locations would make the coast not only a scenic or mobility edge but also a commercial media surface. That raises questions about cumulative impact: whether each site is assessed independently or whether the combined effect of multiple illuminated installations across Mumbai’s shoreline is measured.
The report identifies practical ways to reduce harm if coastal lighting is permitted. Mathi Thumilan, co-founder of Wild and Dark Earth, said warmer-spectrum lighting, lower brightness and timers that reduce intensity after active hours could help. These measures can limit exposure, but they do not remove the underlying planning choice to place illuminated commercial infrastructure beside or on marine habitats.
That distinction is relevant to regulation. Technical controls can reduce brightness or alter the colour spectrum, yet the ecological effect depends on location, duration, intensity, direction and cumulative exposure. A lighting standard designed for streets or buildings may not be sufficient for an intertidal zone. The proposal therefore requires more than a decision about the type of LED used. It requires a framework that identifies sensitive areas, defines acceptable illumination levels, sets operating hours and establishes who will monitor compliance.
The commercial logic is straightforward: coastal billboards create new advertising inventory and potentially new revenue for the agencies controlling maritime or public assets. But the public costs are distributed differently. Advertisers and asset managers may benefit from visibility, while the effects of light pollution are experienced by residents, marine organisms and wildlife that have no role in approving the installation. This is a familiar urban governance problem in a new setting—private revenue generated through the intensified use of shared space, with environmental impacts that may not appear in the project’s immediate financial calculation.
The reported plan also underlines the limits of treating the sea as an empty extension of the city. Mumbai’s waterfront is already used for transport, fishing, recreation, drainage, infrastructure and habitat. A floating billboard may occupy a relatively small physical footprint, but its light can spread beyond the structure and operate through the night. The impact is therefore not measured only by the size of the platform or the number of signs. It is also measured by the area over which illumination changes the conditions of the surrounding water.
What the evidence confirms is that Mumbai’s coastal waters are already exposed to substantial artificial light, marine organisms rely on darkness for migration and feeding, and national and international wildlife-conservation guidelines recognise light pollution as a relevant risk. What remains unclear is whether the Maharashtra Maritime Board has completed environmental impact assessments for the proposed sites, how the 20 locations were selected, what lighting specifications would apply and how cumulative exposure would be monitored.
Those details will determine whether the proposal becomes a controlled coastal-use programme or another incremental addition to Mumbai’s growing night-time infrastructure. The next significant step is the disclosure of the site-specific permissions, environmental assessments, lighting standards and operating conditions governing the proposed billboards.
