Theory:

Conservation of water:
The total quantity of water available on the earth remains constant. This level of water decreases due
to the usage of water by the plants, animals and man and is known as scarcity of water.
The earth has an abundance of water. But, most of it is in the form of ocean and seawater. Only a small fraction of it in the form of groundwater is suitable for the usage of living organisms like plants, animals and humans.
With the drastic decrease in the level of groundwater, the demand for groundwater increases. Groundwater is a renewable resource with high demand as we are using it more than the amount that can be renewed.
Increase in population will spike the demand for groundwater usage for food production industries.  Hence, the conservation of groundwater is very important and essential need.
Reasons of water scarcity:
The main reasons for the scarcity of water are as follows:
  1. Population explosion
  2. Uneven distribution of rainfall
  3. Decline of ground water table
  4. Pollution of water
  5. Careless use of water
1. Population explosion:
With the increase in the population, the demand for the construction of houses, shops, roads, and buildings increases. Due to this, the need for freshwater also rises sharply, and the number of open area places like parks, forests and playgrounds decreases. This reduces the possibility of the rainwater to seep into the ground. This clearly shows that the consumption of groundwater is more than the replenishment of water tables, thereby leading to the depletion of the water table of that region.
 
2. Uneven distribution of rainfall:
Due to a wide range of factors such as rainfall and climatic conditions, the distribution of water across the globe is not even.
Certain places are rich in water due to good amount of rainfall at that place, and other places like the deserts have scanty rainfall.
 
3. Decline of ground water table:
In general the water table is low in the places where there is low or scanty rainfall.
 
4. Pollution of water:
The dumping of organic and inorganic toxic wastes in the water bodies are the reasons for water pollution which makes the water unfit for consumption.
 
5. Careless use of water:
The prevention of water scarcity is important as it is impossible for living organisms to survive without water.  The only method of preventing scarcity of water is conservation of water. This water should be saved for future generations by using water carefully and in a limited way.