Over-population and under-population: Causes and Consequences


Causes of over – population:

  • Birth and Death rates:

Over-population and under-population - Due to improved technology, efficient healthcare and medical facilities global birth rates have soared. The probability of infants surviving beyond the age of five has increased too. Better health care has led to a reduction in mortality rates which causes a lot of growth in the overall population.


  • Poverty:Poverty is also indicative of over – population. Economically stunted nations with low-income rates don’t have the capacity or ability to support growing populations. The mentality of groups or families living below the poverty line not helpful either. They try to cope with poverty by increasing the size of their respective families and increase their income. 
  • Illiteracy and lack of family planning:Literacy and growth rates are directly correlated to each other. Literacy rates in developing nations are pretty low due to their economy being primarily agro-based. Increasing literacy rates improves the general awareness of people and changes their social attitudes and attitudes towards birth control. Lack of efficient and enforced policies related to family planning also leads to over – population. 



  • Depletion of natural resources:Pressure on resources like food and water would increase. Food and fresh water supplies would be inadequate which would result in malnutrition and lowered resistance to diseases. Growing numbers and limited food would lead to an increase in imports which would send economies spiralling into debt. 
  • Environmental hazards:Growth in the population would take its toll on the land, increasing the demand for area which would lead to deforestation or loss of natural habitat. Industrialization and urbanization would increase the global pollutions levels too, causing imbalances in the atmosphere and global warming.


  • Unemployment and poverty:Large populations strain the economy and wouldn’t be able to support themselves due to the scarcity of jobs. A majority of the population would be subjected to poverty and high costs of living due to the sheer pressure on the economy.

    Over-population and under-population

  • Health and sanitation:Haphazard land use and poor infrastructure would lower the quality of health conditions and overall sanitation or hygiene. Inadequate or inaccessible medical facilities would have a negative impact on demographic characteristics like IMR (Infant mortality rate). 
  • Imbalance in trade:Developing countries spend huge amounts of money on medical care, housing and other public facilities. This in turn hinders industrial development and increases the nation’s dependence on developed or advanced countries due to the demand for superior goods and technology. This also occurs due to improper utilisation of resources. 

    Causes of under – population:


  • Sub – fertility rate (total fertility rate):The fertility rate in many developed and developing countries has dropped to about two children per women due to factors like literacy, economic development or urbanization (increasing the cost or standard of living) making the idea of having big families impractical. Changed attitudes toward contraception and an improvement in the social role of females has also affected this demographic attribute. 
  • Emigration:Emigration is the movement of individuals from one country to another with the intention of permanently settling in their destination. Many factors contribute to this type of movement. They can be divided into ‘push’ and ‘pull’ factors. ‘Push’ factors would be the detrimental elements associated with the current region or nation the individuals reside in like lack of employment, oppressive political conditions, poor economies etc. Whereas ‘pull’ factors would be the favourable characteristics of the country the individuals want to move to (like better employment opportunities, political freedom and economic stability etc.) Either way this movement always has a negative effect on the population of the current host. 
  • Disease:Disease and illness has always caused a decline in the population. The emergence of new diseases like HIV/AIDS which has decreased the population globally.

    Over-population and under-population

  • Famine:Famine is the scarcity of food caused due to factors like crop failure and disproportionate population. Being a ‘push’ factor, it has an adverse effect on the population of a region or country. 
  • War and conflicts:People have waged wars since the middle ages and continue to do so. Advanced technology has made modern warfare a huge factor or element in the decline of population. Individuals fighting over resources and space end up killing each other on a massive scale due to the introduction of nuclear and chemical warfare which has a negative effect on the overall population of an area or region.


  • Unstable Economy:Under – population has an adverse effect on the economy causing deflation (decrease in the overall price levels of goods and services). A decline in the population leads to lack of demand.

    Over-population and under-population

  • Decrease in pollution and environmental problems:The pressure on natural resources and the basic infrastructure of an area decreases. Levels of pollutions are cut down too. 
  • Population ageing:Due to decreased rates of procreation, there is an increase in the social and economic pressure on the youth who have to expand the per capita output in order to support the economy. This also leads to a poor quality of life for the youth. 
  • Labour shortage:Declining populations could create labour shortages which could have both positive and negative effects. Labour – intensive sectors of the economy would be adversely affected by such conditions. However a shortage would inevitably increase the demand for labour and potentially reduce unemployment.