The most severe overpopulation pressures today are concentrated in Sub-Saharan Africa and South Asia, where rapid population growth collides with limited infrastructure, food insecurity, and stretched natural resources. But “worst” depends on what you measure: raw population size, growth rate, or the gap between how many people live somewhere and what that place can sustain.
Sub-Saharan Africa Faces the Steepest Climb
Sub-Saharan Africa is the region where population growth most visibly outpaces the systems meant to support it. The average woman in Africa has roughly 2.75 children (as of mid-decade UN projections), well above the global replacement level of about 2.1. In several individual countries, particularly in the Sahel and East Africa, fertility rates remain above 5 or even 6 children per woman. That math compounds quickly: when each generation is significantly larger than the one before, demand for food, water, schools, and jobs grows faster than governments can build them.
Three countries illustrate the strain clearly. Nigeria, already Africa’s most populous nation with over 220 million people, scored 32.8 on the 2025 Global Hunger Index, a figure that actually worsened from 29.9 in 2016. The Democratic Republic of the Congo scored 37.5, categorized as “alarming.” Ethiopia, despite decades of agricultural development, still registered a score of 24.4. In all three cases, population growth is one of several forces (alongside conflict, climate shocks, and governance challenges) driving food insecurity. But it is the force that makes every other problem harder to solve, because the number of mouths to feed keeps climbing even when harvests don’t.
South Asia: Density Without Infrastructure
India surpassed China as the world’s most populous country in 2023, with both nations hovering above 1.4 billion people. The critical difference is trajectory: China’s population is now shrinking, while India’s continues to grow. India’s population is larger than all of Europe and the Americas combined, packed into roughly one-third the land area of the United States.
India’s fertility rate has actually dropped near replacement level nationally, but the country’s sheer size means even modest growth adds millions of people each year. The overpopulation challenge here is less about birth rates and more about density and infrastructure. Cities like Mumbai, Delhi, and Dhaka (in neighboring Bangladesh) hold tens of millions of residents in areas where housing, sanitation, and transportation were designed for a fraction of that number. Bangladesh, with over 170 million people in a country smaller than Iowa, is one of the most densely populated nations on Earth and among the most vulnerable to flooding and sea-level rise, which effectively shrinks the livable land even further.
Growth Rate vs. Overpopulation Strain
The countries with the fastest-growing populations aren’t necessarily the ones feeling the worst overpopulation effects. Qatar led the world in 2024 with a 7.3% annual population growth rate, followed by the United Arab Emirates at 4.7%, Saudi Arabia at 4.6%, and Oman at 4.5%. Almost all of that growth comes from labor migration, not births. These are wealthy Gulf states actively importing workers to build cities and run economies. They have the financial resources to expand housing and services in step with their growing populations, so the lived experience is very different from a country like South Sudan (3.9% growth) where the expansion is driven by high fertility amid poverty, displacement, and limited food production.
This distinction matters. A fast growth rate in a resource-rich country is a policy choice. A fast growth rate in a country that already can’t feed its people is a crisis.
Where Resources Hit Their Limits
Overpopulation pressure shows up differently depending on geography. In the Sahel region (stretching across Mali, Niger, Burkina Faso, and Chad), it looks like shrinking farmland per person as desertification advances and families grow. Niger has one of the highest fertility rates in the world, above 6 children per woman, and one of the lowest levels of arable land productivity. The result is chronic malnutrition and migration toward already-strained cities.
In South and Southeast Asia, the pressure is urban. Megacities absorb rural migrants faster than they can build housing or extend sewage systems. In parts of East Africa, it’s water: aquifers and rivers that served smaller populations are being drawn down to supply growing cities and expanding agriculture simultaneously.
Egypt offers a useful case study of how overpopulation works in practice. Nearly all of the country’s 110 million people live along the Nile River and its delta, a strip of habitable land that makes up roughly 5% of Egypt’s total area. The effective population density in that corridor rivals the most crowded places on Earth, and the government has spent billions building new cities in the desert to relieve the pressure.
The Countries Projected to Feel It Most
By 2050, the UN projects that much of the world’s population growth will be concentrated in a handful of countries: India, Nigeria, the Democratic Republic of the Congo, Ethiopia, Tanzania, Pakistan, Egypt, and the Philippines. Nigeria alone is expected to approach 400 million people, which would make it the third most populous country in the world. The DRC and Tanzania could each roughly double their current populations.
Whether that growth translates into overpopulation crises depends on investment in agriculture, infrastructure, education (particularly for girls, which is the single strongest predictor of declining birth rates), and governance. Some countries will manage the transition. Others, particularly those already struggling with hunger scores in the “serious” or “alarming” range, face a narrowing window to build systems that can keep pace with the people who will need them.