The three main processes of change of population are-birth rates, death rales and miglarion.
(i) Birth rate: It 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 the death rates.
(ii) Death rate: It 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 the death rate.
(iii) Migration: Migration is the movement of people across regions and territories. Migration can be internal (within the country) or international (between countries).