A. Push factors influencing migration:

a. Unemployment: Because of high population pressure on agricultural land and closing down of industries, people are rendered unemployed. In such cases, people migrate to other places to seek employment.

b. Natural disasters: Because of natural disasters such as flood, draught and earthquake, shelters are destroyed and agricultural production and other sources of income suffer. These factors force people to migrate to safer places.

c. Political unrest: Political turmoil or situations like civil war make the surroundings insecure. Therefore, people move to safe places. Example: People migrating from Syria to European countries

B. Pull factors:

a. Better employment opportunities: Industrialised and developed areas are able to provide better job opportunities and higher wages to people. These make these places more attractive and cause migration.

b. Better health and education facilities: Urban or developed areas have better healthcare, education and other facilities which attract people. For example, people migrate from less developed towns to Mumbai and Delhi in search of better educational and health facilities.

The three components of population change are:

 (i) Births

 (ii) Deaths

 (iii) Migration

The impacts of population change:

 (i) Population growth beyond a certain level leads to problems. Of these the depletion of resources is the most serious.

 (ii) Population decline is also a matter of concern. It indicates that resources that had supported a population earlier are now insufficient to maintain the population.

 (iii) The deadly HIV/AIDS epidemics in Africa and some parts of the Commonwealth of Independent States (CIS) and Asia have pushed up death rates and reduced average life expectancy. This has slowed down population growth.

The ratio between the number of women and men in the population is called Sex Ratio.

World pattern of sex ratio :

(i)The world population reflects a sex ratio of 102 males per 100 females. The world pattern of sex ratio does not exhibit variations in the developed regions of the world.

(ii) The highest sex ratio in the world has been recorded in Latvia where there are 85 males per 100 females. In contrast, in Qatar there are 311 males per 100 females.

(iii) The sex ratio is favorable for females in 139 countries of the world and unfavorable for them in the remaining 72 countries listed by the United Nations.

Migration is a response to the uneven distribution of opportunities over space :-

i. People move from place of low opportunity and low safety. This, in turn, creates both benefits and problems for the areas, people migrate from and migrate to.

ii. Consequences can be observed in economic, social, cultural, political and demographic terms.

Economic Consequences :-

i. A major benefit for the source region is the remittance sent by migrants.

ii. Remittances from the international migrants are one of the major sources of foreign exchange.

iii. In 2002, India received US $ 11 billion as remittances from international migrants.

iv. Punjab, Kerala and Tamil Nadu receive very significant amount from their international migrants.

v. The amount of remittances sent by the internal migrants is very meager as compared to international migrants.

vi. Internal Migrants play an important role in the growth of economy of the source area.

Explanations:

 (i) The period from 1901-1921 is referred to as a period of stagnant or stationary phase of growth of India’s population, since in this period growth rate was very low, even recording a negative growth rate during 1911-1921. Both the birth rate and death rate were high keeping the rate of increase low. Poor health and medical services, illiteracy of people at large and inefficient distribution system of food and other basic necessities were largely responsible for a high birth and death rates in this period.

 (ii) The decades 1951-1981 are referred to as the period of population explosion in India, which was caused by a rapid fall in the mortality rate but a high fertility rate of population in the country. The average annual growth rate was as high as 2.2 per cent. It is in this period, after the Independence, that developmental activities were introduced through a centralized planning process and economy started showing up ensuring the improvement of living condition of people at large. Consequently, there was a high natural increase and higher growth rate. Besides, increased international migration bringing in Tibetans, Bangladeshis, Nepalese and even people from Pakistan contributed to the high growth rate.