Explanation

Three- fourth surface of earth (about 71% of total) is occupied by ocean, which contains 97.5% of total water. This is marine water with about 3.5% salt contents. Rest water, i.e., 2.5% is fresh water, which occurs on land. Most amount of this water (about 1.97%, i.e., more than 70% of world’s total freshwater) occurs as frozen polar ice caps and glaciers and 0.5% freshwater occurs as source water.