They convey us that in our country how many different ages of people may it be babies, children, adult, old person are living and finding their ratio so that there will be equal number of population throughout the country

A population pyramid, also called an "age pyramid" is a graphical illustration that shows the distribution of various age groups in a population (typically that of a country or region of the world), which forms the shape of a pyramid when the population is growing. This tool can be used to visualize sex and age composition of a particular population. It is also used in ecology to determine the overall age distribution of a population; an indication of the reproductive capabilities and likelihood of the continuation of a species.

Population pyramid often contains continuous stacked-histogram bars. The population size is depicted on the x-axis (horizontal), and age-groups on y-axis (vertical). Males are conventionally shown on the left and females on the right, and they may be measured by raw number or as a percentage of the total population.

Population pyramids are often viewed as the most effective way to graphically depict the age and sex distribution of a population, partly because of the very clear image these pyramids represent.

A great deal of information about the population broken down by age