What countries pollute the ocean the most?

What countries pollute the ocean the most is typically measured by plastic waste leakage into oceans, and studies show that largest contributors are countries with large populations, high plastic consumption, and inadequate waste management infrastructure, particularly in Asia. According to research on mismanaged plastic waste entering oceans, top contributors include China, Indonesia, Philippines, Vietnam, and Sri Lanka, which together account for large percentage of ocean plastic due to river systems carrying waste. Other studies rank Philippines, India, Malaysia, China, and Indonesia as top sources of ocean plastic leakage via rivers. For overall marine pollution including oil, chemicals, and industrial waste, larger economies like China, United States, and industrial nations contribute significantly through industrial discharge and shipping. For plastic waste per se, China historically was largest, but recent data shows Philippines and India as major contributors due to river pollution. It is important to note that much ocean plastic comes from a relatively small number of rivers, particularly in Asia and Africa, and that developed countries also export waste. So countries that pollute ocean most by plastic are primarily in Southeast Asia including Philippines, Indonesia, Vietnam, China, and India, due to population and waste management challenges.