Question

Why is it necessary to check the population growth?

Answer 1

population growth must be controlled
if population growth becomes uncontrolled then overpopulation may take place that will require more food more shelter to conitnue its existance 
resources in all cases will be exhausted so population must be undercontrolled

Answer 2

Population is one of the most important parts of a nation which manipulates the future of that nation.

That's why tracking and analysing the population is growth is very important because it's help the government to take future steps about the resource distribution,job distribution ,budget implementation and many other important aspects for that nation.

For example ,the 2009's population is obviously less than the current population,so if we follow the population count of 2009 and distribute the resources according to the old census data ,then the majority of population will not get the proper resources.