Question

Why is shortage of water even though almost three - fourth of the earth is covered with water

Answer 1

The water present in larger quantities in the seas and oceans is the salty water that is actually unfit for domestic use. Also the fresh water available is very less in quantity compared to the salty water present and also it is being consumed at faster rate and also being wasted carelessly. Some fresh water resources are also affected due to their pollution from throwing garbage , wastes from industries , bathing of domestic animals , washing of clothes , etc.

Answer 2

there is shortage of water even though almost three - fourth of the earth is covered with water because 75% of the water is sea water which cannot be consumed and only 25 % which is fresh water can be consumed
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out of 100% in fresh water 30% of water among the fresh water constitutes of ground water and only 3% is lakes and rivers and the remaining are in the form of glaciers 
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we get hardly 33% in fresh water which can be used as the remaining is in the form of glaciers