The third component of population change is migration. Migration is the movement of people across regions and territories. Migration can be internal (within the country) or international (between the countries). Internal migration does not change the size of the population, but influences the distribution of population within the nation. Migration plays a very significant role in changing the composition and distribution of population. You will learn more about migration in the forthcoming chapter

We often hear people talk of population growth in alarmed tones. These people are often literate and talk about others not benefitting because there are too many people who have to share very few resources. However, families decide the number of children they want to have based on many considerations such as the resources they own, their security in old age etc. Most often, families with larger number of children are poorer than the rest, don’t own many assets, and rely on their children for old age security. How do we understand these different points of view?

Population density provides a better picture of its distribution. Population density is calculated as the number of persons per unit area.

India is one of the most densely populated countries of the world. The population density of India in the year 2011 was 382 persons per sq km. Densities vary from 1102 persons per sq km in Bihar to only 17 persons per sq km in Arunachal Pradesh. Assom and most of the peninsular states have moderate population densities. Hilly, dissected and rocky nature of the terrain, moderate to low rainfall, shallow and less fertile soils have influenced population densities in these areas. The Northern Plains and Kerala in the south have high to very high population densities because of the flat plains with fertile soils and abundant rainfall

Identify the three states of the Northern Plains with high population densities. How does the density of population vary so much? we have to examine the historyof the region, the terrain and climatic conditions to be able to understand this variation. For example, read the section on ‘Land and other natural resources’ in chapter 8. Even though fertile land and irrigation is able to support a larger population than before, the impact on each group is different,especially for small farmers and land less labours