Every year June 8 is observed as the World Ocean Day to underscore a need to protect the great body of salt water, which covers 70.78 per cent of the earth’s surface. Over two-thirds of the surface of our planet is covered with water. Although this great water expanse is divided into five ocean bodies, it is in fact one vast water body. The ocean acts as a gigantic weather machine for its surrounding land mass and controls wind pressure and temperature of a region. Like landmass, a huge ocean system has several distinct regions. Differences in depth of water, temperature, degree of salinity and presence of oceanic nutrients create habitat for growth of a huge variety of oceanic flora and fauna. It is said that if one cubic of sea water evaporates, it produces 40 million tons of salt. There are three zones in the water of the ocean. The photic zone, euphotic zone or sunlight zone is the depth of the water in a lake or ocean that is exposed to sufficient sunlight for photosynthesis to occur. It extends from the surface down to a depth where light intensity falls to one per cent of that at the surface, called the euphotic depth. Accordingly, its thickness depends on the extent of light attenuation in the water column. Typical euphotic depths vary from only a few centimetres in highly turbid eutrophic lakes, to around 200 metres in the open ocean. It also varies with seasonal changes in turbidity. Since the photic zone is where almost all of the primary productivity occurs, the depth of the photic zone is generally proportional to the level of primary productivity that occurs in that area of the ocean. About 90 per cent of all marine life lives in the photic zone. A small amount of primary production is generated deep in the abyssal zone around the hydrothermal vents which exist along some mid-oceanic ridges. The zone which extends from the base of the euphotic zone to about 200 metres is sometimes called the disphotic zone. While there is some light, it is insufficient for photosynthesis, or at least insufficient for photosynthesis at a rate greater than respiration. The euphotic zone together with the disphotic zone coincides with the epipelagic zone. The bottommost zone, below the euphotic zone, is called the aphotic zone. Most deep ocean waters belong to this zone. The tides are periodic rise and fall of the ocean waters due to rotational movement of the earth and moon and also for the size shape and depth of ocean. The ocean currents and tides beyond normal speed cause unexpected damage to the earth’s surface as they take the shape of cyclone. When the speed is 102-120km per hour, storm is created. Similarly when the wind speed reaches 120 km per hour, it causes hurricane. This year’s global slogan is save islands from oceanic disasters. The reasons are mostly due to pollution and increase in density of sea water. The differences of temperature and increase in salinity bring disastrous situations. The Bay of Bengal as well as the entire Indian Ocean is being constantly polluted by several ways through industrial activities in India. The entire eastern and western coasts are responsible for such pollution. Especially, the metropolitan cities in coasts like Mumbai, Surat, Cochin, Madras, Vishakhapatnam and Kolkata besides smaller cities and towns like Gopalpur, Paradip, Puri, Dhamara and Digha are polluting the sea in various ways. A large number of large, medium and small scale industries are situated through out the coasts. These industries discharge untreated effluents into the ocean through drains, channels, creaks, rivers and rivulets etc. Further, agriculture and prawns and shrimps farming along the sea coasts of Andhra, Tamil Nadu, West Bengal and Odisha discharge large scale organic and inorganic waste into the sea. This pollution is growing up by the day. Although people have demanded for a check in the pollution, the authorities are yet to take steps with sincerity. The country has eleven major ports and several medium and small ports within the coastal regions. Construction activities as well as dredging operations are going on throughout the year for development of each port, leading to erosion of sea shore, siltation of bay and turbidity of sea water and poisoning of the bay water. Several power stations and industrial units release thermal wastes like hot waters and other pollutants in to the sea including fly ash which severally pollute the ocean. The thermal power stations pollute the bay and gulf severely. The sea beds of the Indian Ocean, especially within the coasts of Odisha, Andhra Pradesh, Maharashtra and Kerala are subjected to mining operations as they have vast reserves of several minerals like oil and rare earths. Such operations pollute the water body of the Indian Ocean in various ways and increase the turbidity of the ocean body. The most dangerous operations are mining of oil within the oceanic body. When such operations are carried out, the natural habitats of various sea animals are damaged through the wastes of oil and other ingredients. Besides industrial effluents, untreated domestic garbage in huge quantity is released every day into the ocean from various cities and towns spoiling marine habitats and the environment. Throughout the Indian Ocean, fishing has grown to become a great problem. The use of mechanized boats, trawlers and nylon nets create great problems for various flora and fauna of the oceanic body. Over exploitation of fishes is also a cause of concern. The sea turtles like Olive Ridleys are suffering the most. The wastes of fishing devices create great problem for the oceanic lives. At present, the most disastrous situation is created by chemical fertilizer factories. They release vast effluents into the seas every day through rivers and streams, posing a grave threat to the oceanic biodiversity. Besides, accidents of ships and oil tankers, oil explorations, and drilling operations for various minerals also pose a severe threat to the health of the sea. It is time we should divert much attention to the safety of sea by minimizing pollution. If we continue to be nonchalant, the sea would cause havoc and sea borne disasters would be more lethal and frequent.