Explain the different crisis of population …

Growth of Population: It is the change in the number of people in a particular area at a particular time. It is expressed in percentage. The annual growth rate of India's population in 2001 was 2.4%.
Phases of growth rate of population caused by annual birth rate and death rate:
PHASE I [1901-1921]:

1. Period of stagnant growth.
2. Negative growth was recorded during 1911 to 1921.
3. Birth rate and death rate were high which kept the rate of increase low.
4. Poor health and medical facilities, illiteracy, inefficiency in distribution of food and war were responsible for high death rate in the period.

PHASE-II [1921-1951]:

1. Period of steady population growth.
2. Improved health and sanitation facilities.
3. Better transport and communication means Improved distribution system.
4. Birth rate remained high, leading to high growth rate.

PHASE-III [1951-1981]:

1. Period of population explosion.
2. Rapid fall in death rate but high birth rate.
3. Growth rate was high at 2.2%.
4. Improved medical facilities improved living standard and the growth in economy helped in population explosion.
5. Immigration from neighbouring countries.

PHASE-IV [1981-2001]:

1. Growth rate declined due to crude decline in birth rate.
2. Increase in the mean age of marriage.
3. Improved literacy, specially among females.