Big growth of tourism and commerce leads to higher demand for maritime traffic, which creates higher demand for number and tonnage of ships. Growth of ship numbers leads to increase of pollution which arise from exploitation of ships, but due to development of technology increase of tonnage of ships in the world doesn’t lead to increase of pollution, but contrary in some cases level of pollution from ships shows trend of lowering. Decrease of pollution along with technology is caused also by provisions of International Maritime Organization (IMO) and some other local organizations which are increasingly rigorous with demands for compliances for protection of environment.The aim of this thesis is to present regulations and technologies which contribute to reduction of pollution and present on which ways modern ship pollutes environment. New technologies that are introduced for prevention and reduction of pollution require education of people how to properly use them, what are their benefits in term of efficiency and savings along with information how to prevent pollution and rigorous fines used to sanction polluters of environment. Thesis discusses the ways how ship pollutes environment, ways of prevention of pollution along with technologies and international regulations about different kind of pollution. Thesis will contain examples of good practice on term of reduction of pollution that were introduced by individual companies and my own researches about impact of maritime traffic on quality of air in Dubrovnik.