The problem is infrastructure, not individual behaviour. In many coastal communities across Southeast Asia, West Africa, and Central America, there are no collection trucks, no transfer stations, no managed landfills. Residents dispose of waste in the nearest open space — often a riverbank, drainage ditch, or beach. When that waste includes plastic — and in the modern economy, it almost always does — the ocean is the final destination.

Open dumpsites near coastlines are another major source. The International Solid Waste Association (ISWA) has documented thousands of uncontrolled dump sites within 10 kilometres of coastlines in low-income countries. These sites have no liners, no covers, and no leachate management. Plastic blows off the pile, washes away in rain, and migrates steadily toward the water.

This pathway is also where prevention delivers the greatest return. Collecting plastic in a coastal community before it enters the water costs a fraction of what it takes to intercept it in a river — and is orders of magnitude cheaper than retrieving it from the open ocean. In coastal communities across the Philippines, Indonesia, Brazil, Egypt, and Thailand, Plastic Bank operates collection branches where community members earn income by gathering plastic waste. This approach intercepts plastic at the most critical point — before it enters rivers and coastal waters. As of March 2026, collection community members have gathered over 9.4 billion plastic bottles through the programme, according to Plastic Bank's live tracker.

The economics are straightforward: giving plastic value in the community where it is discarded stops it from becoming pollution. When plastic waste turns into an income source, people collect it instead of discarding it.

How Do Maritime Activities Add Plastic to the Ocean?

Not all ocean plastic comes from land. An estimated 20% originates from maritime sources — commercial fishing, shipping, offshore energy production, and aquaculture, according to the International Maritime Organization.

Fishing gear is the dominant sea-based source. The Food and Agriculture Organization (FAO) estimates that approximately 640,000 tonnes of fishing nets, lines, traps, and pots are lost or abandoned in the ocean every year. This "ghost gear" does not stop working when it is lost. Abandoned nets continue to trap and kill marine life for years, a phenomenon called ghost fishing. Ghost nets make up a significant portion of the plastic debris in the Great Pacific Garbage Patch, where fishing gear accounts for an estimated 46% of the total mass.

Shipping containers fall overboard more often than most people realise. The World Shipping Council reported an average of 1,566 containers lost at sea annually between 2020 and 2023. Each container can hold tonnes of consumer goods, many packaged in plastic. When containers breach in the water, their contents scatter across hundreds of kilometres of ocean surface.

Offshore oil and gas platforms generate plastic waste through equipment degradation, packaging disposal, and operational spills. While regulations require these facilities to manage waste onshore, compliance varies and enforcement is difficult in international waters.

Aquaculture — fish and shellfish farming — is a growing source of marine plastic. Buoys, cages, ropes, and feed bags made from plastic degrade in seawater and release fragments into the surrounding environment. As the aquaculture industry expands to meet global protein demand, so does its plastic footprint.

Can Wind Carry Plastic into the Ocean?

Yes. Lightweight plastics — bags, film, polystyrene foam, and microplastic particles — are transported by wind from landfills, streets, construction sites, and agricultural fields, sometimes travelling hundreds of kilometres before landing in the ocean.

Wind transport has long been underestimated as a pathway. But a growing body of research shows that atmospheric deposition of microplastics is a significant source of ocean contamination. Scientists have found microplastics in the air above remote mountain ranges, in rainfall samples from U.S. national parks, and in fresh snow in the Arctic.

A 2019 study in Science documented microplastic "rain" falling on protected wilderness areas in the western United States, far from any urban source. The researchers estimated that over 1,000 tonnes of microplastic particles fall on U.S. national parks and wilderness areas each year — equivalent to more than 120 million plastic water bottles.

Wind-blown macroplastics are more visible. Anyone who has walked near a landfill on a windy day has seen bags and packaging sailing over fences and boundaries. Coastal landfills are especially problematic: plastic blown from waste piles can reach the ocean within minutes. Construction sites that use plastic sheeting, foam insulation, and plastic-wrapped materials are another common source of wind-dispersed plastic.

Atmospheric transport means that even landlocked plastic waste contributes to ocean pollution. A plastic bag discarded in a city 500 kilometres from the coast can be lofted by wind, deposited in a river catchment, carried downstream, and reach the ocean, a journey that may take weeks or months but happens continuously at scale.

Where Is Intervention Most Effective?

Not all plastic pollution interventions are equal. The cost per kilogram of plastic removed varies by orders of magnitude depending on where in the pathway you act.

Community collection (before plastic reaches waterways): This is the cheapest and most effective intervention point. Collecting plastic waste in a community, especially in coastal areas without formal waste management, prevents it from entering rivers and oceans at a fraction of the cost of downstream recovery. Programmes that pay collection community members to gather plastic, like those operated by Plastic Bank, combine pollution prevention with poverty reduction.

River interception: Barriers, booms, and collection vessels deployed in high-emission rivers can capture significant volumes of plastic before it reaches the ocean. The Ocean Cleanup's Interceptor technology targets the 1,000 rivers responsible for most riverine plastic. River interception works, but it costs more per kilogram than community collection and cannot catch microplastics that pass under or through barriers.

Ocean cleanup: Removing plastic from the open ocean is the most expensive option by far. The logistical costs of operating vessels across millions of square kilometres, the fuel consumption, and the difficulty of separating plastic from marine life make ocean cleanup roughly 10 to 100 times more costly per kilogram than land-based prevention. Ocean cleanup addresses the symptom, not the cause.

Policy solutions: Extended Producer Responsibility (EPR) laws, single-use plastic bans, and deposit return schemes tackle the problem at the production and consumption stages. EPR legislation forces the companies that create plastic packaging to fund its end-of-life management. Deposit return schemes — where consumers pay a small fee on a bottle and receive it back when they return the bottle for recycling — have achieved return rates above 90% in countries like Germany and Norway.

The numbers confirm what field workers already know: preventing plastic from reaching the ocean is cheaper, faster, and more effective than pulling it out once it is there. Investment in waste collection infrastructure in high-leakage coastal communities delivers the highest return per dollar spent.

For more on the scale of ocean contamination, read our guides on how much plastic is in the ocean, ocean pollution facts, and the growing problem of trash in the ocean. You can also explore our companion article on plastic pollution in the ocean for a broader look at the crisis.