How is water distributed on earth?
We know that around 71% of the earth is covered with water.
About 97% of this is saltwater and the remaining 3% is fresh water. About 69 % of the freshwater is frozen in the ice caps and glaciers. And the remaining 30% of this 3% is present as soil moisture, or lies deep underground and is not accessible for human use. So only about 1% of this freshwater is accessible for direct human uses! This is the water found in lakes, rivers, reservoirs and those underground sources that are shallow enough to be tapped at an affordable cost. Even this 1% of freshwater is not available everywhere. Therefore, there are some places which suffer from water shortage.
Distribution of water on earth
What is Water pollution?
Water pollution is the contamination of water bodies, usually as a result of human activities. Water pollution can happen in two major ways:
(i)Â Addition
Removal
 Addition: When we add undesirable substances into the water, it proves harmful to the living organisms living in it as well as to us who drink this
For instance, when we spray excess pesticides and fertilizers in our farms, they dissolve in the water and sometimes may find their way into the freshwater. We also let our sewage into lakes and the seas. In villages, people wash their cattle in the public pond. All these activities lead to the addition of germs and chemicals in the water.
Sometimes industries use water as cooling agents, and this heated water is discharged into the water body. The sudden change in temperature of the water body will kill the aquatic animals.
Removal: Sometimes, we use oxygen from the water and also some nutrients and then send the water devoid of major nutrients back into the water body. This makes the water polluted as well and unfit for the marine animals