Processes of Population Change/ Growth

• Birth rate
• Death rate
• Migration

Processes of Population Change/Growth

• Population changes by three main processes. These are birth rates, death rates and migration.
• The difference between birth and death rates is the natural increase in population.
• Birth rate is the number of live births per thousand persons in a year. It is a major component of growth because in India, birth rates have always been higher than death rates.
• Death rate is the number of deaths per thousand persons in a year. The main cause of the rate of growth of the Indian population has been the rapid decline in death rates.
• Until 1980, a large difference between birth and death rates resulted in higher rates of population growth due to high birth rates and declining death rates. Since 1981, birth rates have gradually declined, resulting in a gradual decrease in the rate of population growth.
• Migration is the third component of population growth. Migration is the movement of people across regions and territories. It can be internal (within the country) or international (between the countries).
• The size of the population does not change due to internal migration, but it does influences the distribution of population within the nation. Migration plays a very important role in changing the composition and distribution of population.
• People in India migrate from rural to urban areas because of the existence of "push" factor in rural areas such as lack of job opportunities, poverty, etc. Whereas people get attracted towards i.e. they get pulled by increased employment opportunities and better living conditions of urban areas. This act as a "pull" factor. 
• Migration is a significant determinant of population change. It alters not only the population size but also the age and sex composition of urban and rural populations. In India, rural-urban migration has resulted in a steady increase in the percentage of population living in cities and towns. The urban population has grown from 17.29% of the total population in 1951 to 31.80% in 2011. In just one decade, from 2001 to 2011, the number of "million plus cities" increased from 35 to 53.