Quick Revision Notes & Formula Sheet

Class 9 Social Science (Geography)

Population: The total number of people living in a particular area (country, state, district, etc.) at a specified time.
Census (जनगणना): An official enumeration of population done periodically in India (every 10 years). The first census in India was held in 1872, and the first complete census was taken in 1881.
Significance of Population: People are the nation's most important resource. They are producers and consumers of Earth's resources.

Population size and distribution change primarily through three processes:

Birth Rate (Crude Birth Rate - CBR):
- Definition: The number of live births per 1,000 persons in a year.
- Formula: Birth Rate = (Number of Live Births / Total Population) × 1000
Death Rate (Crude Death Rate - CDR):
- Definition: The number of deaths per 1,000 persons in a year.
- Formula: Death Rate = (Number of Deaths / Total Population) × 1000
- Note: Rapid decline in death rates is the main cause of population growth in India.
Migration (प्रवास):
- Movement of people across regions and territories.
- Internal Migration: Within the country (changes distribution, not size).
- International Migration: Between countries (changes both size and distribution).
- Push Factors: Adverse conditions (poverty, unemployment) that push people out.
- Pull Factors: Favorable conditions (job opportunities, better living conditions) that attract people.

Total Population: As per the 2011 Census, India’s population stood at 1,210 million (1.21 billion), accounting for 17.5% of the world's population.
Geographical Distribution:
- India’s population is unevenly distributed due to varied terrain, climate, and resource availability.
- Uttar Pradesh is the most populous state (holds roughly 16% of India's population).
- Sikkim has the least population, and Lakshadweep has the smallest population among UTs.
Population Density (जनसंख्या घनत्व):
- Definition: The number of persons per unit area (per square kilometer).
- Formula: Population Density = Total Population / Total Land Area (in sq. km)
- India's population density in 2011 was 382 persons per sq. km.
- Bihar has the highest population density, while Arunachal Pradesh has the lowest.

Population Growth Rate: Expressed in percentage per annum (e.g., an increase of 2% per year).
Absolute Increase: The actual numbers added each year or decade by subtracting the earlier population from the later population.
India's Growth Trend: Population grew steadily from 361 million in 1951 to 1,210 million in 2011. However, since 1981, the growth rate started declining gradually as birth rates declined.

Demographic structure affects socio-economic development. Key components include:

Divided into three broad categories:

Children (0–14 years): Economically unproductive, require food, clothing, education, and medical care.
Working Age (15–59 years): Economically active and biologically reproductive. The workforce of the nation.
Aged (60 years and above): Economically retired, though they may be working voluntarily.

Definition: The number of females per 1,000 males in the population.
Formula: Sex Ratio = (Total Number of Females / Total Number of Males) × 1000
In India (2011 Census), the sex ratio was 943 females per 1000 males.
Kerala had the highest, while Haryana/Punjab regions historically recorded lower ratios.

Definition: According to the 2011 Census, a person aged 7 years and above who can read and write with understanding in any language is treated as literate.
India's overall literacy rate (2011) is 74.04% (Male: 82.14%, Female: 65.46%).
Kerala leads in literacy, whereas Bihar has the lowest.

The distribution of population according to different types of occupations:

Primary Activities: Agriculture, forestry, fishing, animal husbandry (majority of India's population works here).
Secondary Activities: Manufacturing industry, building, construction work.
Tertiary Activities: Transport, communication, commerce, administration, and services.

Trend: Increasing percentage of the population is shifting towards secondary and tertiary sectors due to economic development.

Generally grouped in the age group of 10 to 19 years.
They represent the future human resource of India.
Key Needs: Balanced diet, awareness against nutritional deficiency, education, and prevention of early marriage/substance abuse.

Recognizing the importance of population as a resource, the Government of India initiated the National Population Policy (NPP) 2000.
Objectives:
- Imparting free and compulsory school education up to 14 years of age.
- Reducing infant mortality rate (IMR) below 30 per 1,000 live births.
- Achieving universal immunization of children against all vaccine-preventable diseases.
- Promoting delayed marriage for girls.
- Making family welfare a people-centered program.