Mangrove ecosystem is a very unique ecosystem in the Earth, which is under threat due to habitat loss, aquaculture expansion, overharvesting and increase of pollution load. In this review paper, world-wide status of mangrove habitat loss, role of mangrove to act as a sink of pollutants and carbon capture (carbon sequestration), accumulation and biomagnifications of heavy metals is discussed. Emphasis has been given to understand the effect of heavy metals, organic and inorganic pollutants on the mangroves and the natural ability of this ecosystem to tolerate the pollution load. Lastly the guidelines of mangrove research for the developing countries are also suggested.