Birth rate = 50/1000/year, Death rate = 50/1000/year
Net growth rate r = 50 − 50 = 0
Population change = r × N = 0 × 10,000,000 = 0
Final population = 10,000,000 = 10 million
Answer: 10 million
The fundamental population growth equation for a closed population (no immigration/emigration): dN/dt = (b − d) × N = r × N, where b = per capita birth rate, d = per capita death rate, r = intrinsic rate of natural increase = b − d, N = current population size. When b = d: r = 0, dN/dt = 0 → population constant. Exponential growth: N(t) = N₀ × e^(rt). If r = 0: N(t) = N₀ × e⁰ = N₀ × 1 = N₀. Population stays constant, as in this question where r = 50/1000 − 50/1000 = 0.
Birth rate (natality) is the number of births per unit time per unit population, commonly expressed per 1000 individuals per year. Death rate (mortality) is similarly expressed. These rates together determine the natural rate of increase. Adding immigration rate (I) and subtracting emigration rate (E) gives the complete demographic equation: ΔN/year = (b − d + I − E) × N. For this question, only births and deaths are considered (closed population), so ΔN = (50/1000 − 50/1000) × 10,000,000 = 0. Population at end of year = 10,000,000 = 10 million, unchanged.
Countries progress through predictable stages of demographic change called the demographic transition: Stage 1 (pre-industrial): high birth rates + high death rates → slow/stable population growth. Stage 2 (early industrial): death rates fall (improved sanitation, medicine) but birth rates remain high → rapid population growth. Stage 3 (industrial): birth rates start falling (education, urbanisation, contraception) → growth slows. Stage 4 (post-industrial): both birth and death rates low → near ZPG. Stage 5 (some developed nations): death rate slightly exceeds birth rate → population decline. Most developing nations are in stages 2-3; developed nations in stages 4-5.
India has pursued active population management policies since the 1950s. The National Family Planning Programme (1952) was the world's first government-sponsored family planning programme. Key milestones: 1950-2000s saw fertility decline from TFR ~6 to ~2.5. Reproductive and Child Health (RCH) programme replaced the coercive sterilisation approach with voluntary family planning. National Population Policy 2000 targets: TFR of 2.1 by 2010 (achieved nationally around 2018-2020). Kerala and Tamil Nadu achieved replacement fertility much earlier (demonstrating that female education and healthcare reduce fertility without coercion). India's demographic dividend (large working-age population) can drive economic growth if leveraged with adequate jobs and education.
Population age structure (the proportion of individuals in different age groups) profoundly influences future population growth, independent of current birth and death rates. Pyramid-shaped age structure (wide base, narrow apex): large proportion of young people → high future birth rates even if fertility falls. This is called population momentum — reason why India's population will continue growing for decades even though TFR has reached near-replacement level, because there are so many young people not yet in reproductive age who will have children. Column-shaped structure (equal proportions across ages): stable population. Inverted pyramid (narrow base): declining population (Japan, Germany currently experiencing this). Understanding age structure is crucial for projecting future population trends and planning healthcare, education, and pension systems.
World population reached 8 billion in November 2022. Growth rate is declining globally — from ~2% per year in 1960s to ~0.9% today. UN median projection: world population peaks around 10-11 billion in 2080s then slowly declines. Fastest growing regions: sub-Saharan Africa (high fertility). Declining populations: Japan, South Korea, many European nations. Implications: ageing populations in developed world (more elderly, fewer workers), young growing populations in developing nations (demographic dividend or burden depending on education/employment). Global resource constraints (food, water, energy) make population stabilisation a critical sustainability challenge.