Plastic pollution is harming oceans and marine life, but sustainable alternatives are often not able to compete in mainstream markets, according to UN reporting. The UN highlights that alternatives—such as products made from seaweed—face economic and regulatory barriers that slow their scale-up and limit market access. One challenge is tariffs and other trade measures that can raise the cost of importing or producing sustainable materials, making them less competitive than conventional plastic. Another challenge is fragmented regulations: rules that differ across countries can create uncertainty for producers and complicate compliance and supply chains. In parallel, fossil fuel-based plastics benefit from an entrenched market advantage, supported by established production systems and widespread availability. As a result, even when sustainable options exist, their uptake can be constrained by higher upfront costs, uneven policy conditions, and limited commercial competitiveness. The reporting focuses on the structural factors that affect the pricing and adoption of greener materials, rather than on any single product or country.