A lot of the their age structure is filled with young children, those kids are getting married at this stage and now they are having kids. That increases the population.
Unemployment: For everyone to get a job in a country like India is very difficult. The number of illiterate people increases every year. Every year the amount of unemployed people keeps rising.
Resource utilisation: Lack of land, clean water, deforestation. Demand would be very high and there would not be enough resources to supply the people.
Terrain: There are quite a few mountains and slopes, that restricts farming, a lot of transport, that creates a lot of economic barriers, this makes people want to live in the cities and not in the mountainous regions.
Climate: 2 main downfalls in India, rainfall and temperature that influences the population a lot, because how hot/cold it is in a area is a factor which decides if people should live there or not.
Water: Availability of water plays a significant role in determining the population of an area. Water is necessary for life, agriculture is very important in India, without water that would make agriculture very hard. Rivers are the greatest source of fresh portable water. Most of the population is concentrated next to rivers, lakes and large bodies of water.
India has a long history of migration. More than a century ago, large numbers of Indian migrants, a lot of them which were forced too, moved to Africa, the Caribbean and within different cities in India itself.
A lot of Indians have migrated globally, every one in twenty migrants that you find worldwide was born in India. 15.6 million people born in India were living in other countries. (2015)
A lot of Indian migrants go to UAE, Pakistan and the US.
India at the same time, is also one of the world’s top destinations for international migrants. 5.2 million immigrants live in India, making it the 12th-largest immigrant location in the world. (2015)
A lot of these immigrants are coming from neighbouring countries such as Bangladesh, Pakistan, Nepal and Sri Lanka.
This means that people are leaving the country at a high rate and entering the country at a high rate, but more people are leaving the country at a higher rate.
These are usually economic, social and political factors.
Marriage is a very important social factor of migration. Every girl has to migrate to her husbands place after marriage. That means that a lot of the female population of India has to migrate over short or long distance.
Education: Rural areas lack education, especially higher education and rural people have to migrate to the urban centres for good education. Many of them later then settle down in those cities to earn a living after completing their education.
Employment: People migrate in large numbers from rural to urban areas in search of employment. Agriculture does not provide to everyone living there in the rural areas. So people would ruther go in to the cities to get higher paying jobs.
As we can see a lot Indias population tend to be on the young side and quite a few middle aged people, and not so many aged people. This is very good for the future of India. There seems to be more males then females, but its quite even.