Globalization and the growth of world trade have caused a strong development of transport, and the same applies to maritime traffic. It transports the world's largest share of goods, but it isn't without any environmental difficulties. Problems arise with oil spills to the sea that are cumulatively very damaging; with the discharge of harmful wastewater into the environment and impairment of attractiveness; with the exchange of ballast water that carries potential invasive species with it; with marine waste that doesn’t majorly come from ships but harms organisms and can cause damage to vessels; with emissions of nitrogen oxides, and sulfur oxides and particulate matter that worsen the air quality, especially around ports. More specific difficulties come with ship-breaking, which degrades the environment and offers jobs in poor working conditions in developing countries, and cruises, which make ships into traveling hotels with large amounts of pollution. These are the examples that will be addressed in this thesis to see how severe their consequences are, but it is also necessary to see how the road to sustainability is going and how maritime transport can become cleaner.