The correct option is 2 only.
Explanation
Population growth refers to the change in the number of inhabitants of a territory during a specific period. It can be expressed in absolute numbers or as a percentage. In India, population trends are analyzed using decadal growth rates and average annual exponential growth rates derived from Census data.
Statement-wise Analysis:
- Statement 1 is Incorrect: According to the 2011 Census, the average annual exponential growth rate of India's population during the period 2001-2011 was 1.64 %. A growth rate of around 2.2 % was observed during the 1971-1981 decade. The figure of 2.5 % is factually incorrect for the 2011 census period.
- Statement 2 is Correct: Population doubling time is a standard demographic metric defined as the time required for a population to double in size at a constant annual growth rate. It is calculated using the rule of 70 (Doubling time ≈ 70 / annual growth rate). As the growth rate declines, the doubling time increases.
- Statement 3 is Incorrect: The decadal growth rate of India's population has been showing a declining trend. The growth rate during 1991-2001 was 21.54 %, whereas it fell to 17.64 % during 2001-2011. Therefore, the growth rate in the 2001-2011 decade was lower, not higher, than the previous decade.
Key Takeaway:
India entered a phase of declining fertility and growth rates after 1981. While the absolute population continues to increase, the rate of growth (both annual and decadal) has been consistently falling since the 1971-81 peak.