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Public health and development: Infrastructure, social norms, and health behaviours

2 What are the facts?

The mortality rate refers to the number of deaths within a specific population (for example, per 100,000 people) over a period of time.

Public health is a field of medicine that focuses on community-wide health. Public health comprises several dimensions, including infrastructure to provide clean water and sanitation, access to vaccines, access to medical drugs, preventive care, treatment, and institutional deliveries (giving birth in medical institutions under the care and supervision of trained health care providers).

Through much of human history, the health of individuals has been treated as something that was beyond their control: ‘health fell largely under the influence of religion and was equivalent to gaining favor with deities. Religious healers believed that in order to achieve health, it was necessary for individuals to pray and sacrifice to the gods in order to propitiate them.’1 Despite medical advances through the centuries, it was only in the eighteenth century that the Enlightenment applied reason and observation of evidence, and established the idea that societies could improve their well-being by reforming their environment. As this Insight will show, OECD countries made major investments in public health infrastructure in the nineteenth and twentieth centuries. Such investments drastically reduced mortality rates and improved welfare. In low-income countries, while there have been many small interventions, people in those countries still face challenging health outcomes and a big push in infrastructure investment is needed. Poor health, in the form of chronic diseases and childhood malnutrition, affects adult productivity, which in turn affects income and hampers economic growth.

To explore the data on healthcare expenditure and national income, visit Our World in Data’s web pages on healthcare expenditure vs GDP per capita and government healthcare spending as a share of GDP.

Figure 1 shows the incidence of different causes of death in high-income and low-income countries. The main difference between these groups of countries is that most fully preventable deaths, such as death from diarrhoeal disease, occur in low-income countries. One of the main challenges today is how to develop health services in low-income countries in a way that reduces fully preventable deaths.

World Low-income countries High-income countries
Deaths per 100,000 731 728 917
Percentage of total deaths by age
Children (0–4) 9.48 32.97 0.61
Elderly (60+) 65.92 31.89 85.27
Percentage of deaths from chronic diseases
Cancer 16.63 7.68 24.76
Cardiovascular disease 32.76 16.79 34.82
Number of deaths, millions
Respiratory* 4.27 0.14 0.70
HIV/AIDS 0.71 0.17 0.04
Neonatal deaths* 2.06 0.54 0.03
Diarrhoeal diseases 1.32 0.26 0.03
Tuberculosis 1.33 0.22 0.02
Malaria 0.58 0.26 –
DPT/Measles 0.29 0.12 –

Figure 1 The worldwide structure of mortality in 2019.

Author’s elaboration based on WHO data from 2019 (the last data available prior to the COVID-19 pandemic).
Note: DTP stands for diphtheria, tetanus, and pertussis (whooping cough). An asterisk (*) indicates that the disease is most commonly fatal in children, except respiratory disease in high-income countries. – indicates less than 10,000 deaths. ‘Low-income’ and ‘high-income’ are World Bank designations of countries. The relatively high number of deaths from respiratory illness in high-income countries compared to low-income countries is due to the different age profiles (low-income countries have younger populations and have implemented vaccine programmes that reduce child mortality from respiratory infections, while high-income countries have older populations so these deaths include people who die of respiratory illness in old age.

life expectancy
The average number of years of life remaining to a person at a particular age and based on a given set of age-specific death rates—generally, the mortality conditions existing in the period mentioned. Life expectancy may be determined by sex, race, or other characteristics, by using age-specific death rates for the population with that characteristic.

To learn more about the research on income and health, read these articles:

Pascaline Dupas and Edward Miguel. 2017. ‘Impacts and Determinants of Health Levels in Low-Income Countries’. In Handbook of Economic Field Experiments Vol. 2. Eds. Abhijit Banerjee and Esther Duflo. North Holland. pp. 3–93.

Angus Deaton. 2003. ‘Health, Inequality, and Economic Development’. Journal of Economic Literature 41(1): pp. 113–158.

Joe Brown, Sandy Cairncross, and Jeroen H. Ensink. 2013. ‘Water, Sanitation, Hygiene and Enteric Infections in Children’. Archives of Disease in Childhood 98(8): pp. 629–934.

The link between higher income and better physical health has been widely documented. Indicators of better physical health include higher life expectancy, lower child mortality, and lower incidence of diseases. Higher income affects health through several channels. Firstly, since better health is desirable, when income increases, people will spend more on ways to improve health, such as better nutrition and seeking better medical care. Secondly, richer economies usually invest more (both as a percentage of GDP and in dollar terms) in health services and have better infrastructure to cope with curable diseases. However, governance and institutions affect investment in healthcare and access to it. OECD countries, which have invested heavily in developing different public health systems, still show substantial inequalities in healthcare coverage between and within countries.2

Child mortality

One of the main developmental achievements registered worldwide has been the reduction of child mortality, defined by the World Health Organization as the probability that a child born in a specific period will die before reaching the age of five years. This decline is a recent phenomenon: Figure 2 shows that two centuries ago, child mortality was as high as 55%, but it had fallen to a global average of 4.3% by 2020. But Figure 3 shows that there is variation in how much child mortality has reduced, with OECD countries’ rates falling earlier than those of other regions like Asia and Africa. The improvement in child mortality can be associated with factors such as mass vaccination campaigns, progress in medicine such as antibiotics, disease eradication, increase in institutional deliveries, better nutrition, and (in particular) clean water and sanitation. Clean and drinkable water provision and safe disposal of human faeces has been one of the main causes in the reduction of preventable deaths.

This scatterplot chart highlights the dramatic historical decline in child mortality, especially during the twentieth and early twenty-first centuries. It shows child mortality rates (in percentages) from 300 BCE to 2020 across various historical societies and modern countries. The vertical axis measures child mortality rate, while the horizontal axis spans from 300 BCE to 2020. Ancient and premodern societies such as Roman Egypt (year 0 CE), Teotihuacan (Mexico, 550–700), and Wari (Peru, 600–1100) display extremely high child mortality rates, between 50% and 60%. Similarly, early modern European regions like Poland (1875), Venice (1800–1900), and France (1816–1850) also exhibit rates above 40%. By contrast, global child mortality drastically drops from 35% in 1950 to under 4% globally by 2020. Some countries such as Iceland, Finland, Norway, Japan, and Slovenia reach near-zero levels in 2020, while Somalia still reports relatively high rates (by 2020 standards), around 10%.
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Figure 2 The long-run history of child mortality.

This line chart shows the child mortality rate (in percentages) on a time series from 1950 to 2022 across six global regions: Africa, Asia, Latin America, Europe, Oceania, and Northern America. Africa begins with the highest child mortality rate—over 30% in 1950—and shows a steady decline, though remaining the highest throughout the period. Asia and Latin America also begin with relatively high rates (above 20%) and demonstrate consistent reductions, with Latin America falling below Oceania after the 2000s. Europe and Northern America start with lower child mortality rates and approach near-zero levels by 2022. Oceania experiences a gradual decline, remaining between Europe, Northern America, and Latin America.
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Figure 3 Child mortality rates by region (1950–2023).

Question 1 Choose the correct answer(s)

Read the following statements about healthcare coverage and mortality rates, and choose the correct option(s).

  • The reduction in child mortality is a recent historical phenomenon.
  • Child mortality fell first in OECD countries and then in middle-income countries.
  • Most deaths attributable to preventable diseases now occur in low-income countries.
  • Healthcare coverage within OECD countries is uniform across the population.
  • Figure 2 shows that two centuries ago, child mortality was as high as 40%, but it had fallen to a global average of 4.3% by 2020.
  • Figure 3 shows that there is variation in the reduction in child mortality, with OECD countries’ rates falling earlier than those of other regions like Asia and Africa.
  • Figure 1 shows that the deaths attributable to preventable diseases are generally higher in low-income countries than high-income countries. However, these deaths in middle-income countries (which you can calculate by subtracting the low-income and high-income numbers from total deaths) are generally even higher.
  • OECD countries still have inequalities in healthcare coverage. Not all members of the population have the same access to healthcare.

Water, sanitation, and hygiene (WASH)

This Insight focuses on water, sanitation, and hygiene (WASH), because of its contribution to preventable deaths. The United Nation’s sixth Sustainable Development Goal (SDG) is to ‘Ensure access to water and sanitation for all.3 Access to safe water, sanitation and hygiene is the most basic human need for health and well-being.’ This objective will not be fulfilled by 2030 unless efforts substantially intensify.

To understand the challenges for low-income countries of improving health and reducing child mortality through water and sanitation provision, it is helpful to look first at the experience of OECD countries during the nineteenth and early twentieth century. Figure 4 tracks the progress in the provision of clean water and safe human waste disposal in some high-income countries. Main infrastructure works on water provision and sewage started at around 1850 in England, followed by other countries such as Germany, France, and the US. Between 1850 and 1940, industrialized countries invested in improving clean water provision and building sewage systems in major urban areas. There were three main factors behind this trend:

  • advances in epidemiology and the study of how individual health might be affected by societal factors
  • increased demand for better services in rapidly growing urban areas; contaminated water and inadequate sewage caused disease outbreaks which resulted in deaths; the risk of uncontrolled fires in wood buildings also increased the need for water
  • technological change in the methods used to supply water and dispose of human waste (steam engines, metal piping, and water chlorination at the beginning of the twentieth century).

Data for that period is scarce, but Figure 4 shows a sharp increase in industrialized countries’ waterworks and sewerage systems coverage between 1870 and the 1910s.

Waterworks Sewerage systems
1870 1880 1890 1900 1900–1910s
England and Wales
Number of cities – 212 250
% of large towns – 95 95
United States
Number of cities 99 160 201 145
% of large towns 49 78 99 71
Germany
Number of cities 37 121 203 269 264
% of large towns 13 42 70 92 91
The Netherlands
Number of cities 2 6 23 32 17
% of large towns 6 17 66 91 49

Figure 4 Diffusion of waterworks and sewerage systems in some selected countries (1870–1910s).

Note: The data provided for towns concentrates on large towns, with populations over either 10,000 or 15,000 measured in a year between 1880 and 1900. England and Wales: towns over 10,000 in 1880. United States: towns over 15,000 in 1890. Germany: towns over 15,000 in 1900. The Netherlands: towns over 15,000 in 1899.
Daniel Gallardo-Albarrán. 2024. ‘The Global Sanitary Revolution in Historical Perspective’. Journal of Economic Surveys 39(2): pp. 1–32.

In contrast, by 1938, poorer countries had much lower coverage. For example, Colombia had achieved 61% of waterworks coverage and 42% sewage for its cities with more than 15,000 inhabitants. These numbers do not account for the variation in coverage within cities. There is evidence that households covered within a given city varied because of social or political discrimination. In the US, for example, areas primarily occupied by African Americans or Native Americans had much lower coverage rates than other areas in the same cities.

After 1950, water provision coverage and sewage systems were built in urban areas in other regions (such as Latin America and parts of Asia), but there is no systematic cross-country data available to look at the evolution of coverage during this period. Additionally, many urban areas in middle-income countries had even wider disparities in the proportion of households serviced by clean water and sanitation than those of OECD countries half a century before. For example, Indian cities like Mumbai, Kolkata, and Chennai Madras received many migrants, and suffered water shortages and sanitation crises periodically due to high population growth.4 Figure 5 shows the low coverage for water and sanitation in Kolkata in 2011.

Statistics
Domestic water use 130 litres per capita per day
Households with water access 79%
Water loss due to leakage in pipe 35%
Households with sewerage services 52%
Wastewater treated 20%
Main water sources Surface water from the Hugli branch of the Ganges
Groundwater from deep and hand tube wells
Main water problems Water use inefficiency
Pollution
Flooding
Ecosystem destruction
International dispute

Figure 5 Water statistics in Kolkata.

Rana P. B. Singh, Md Senaul Haque, and Aakriti Grover. 2015. ‘Drinking Water, Sanitation and Health in Kolkata Metropolitan City: Contribution Towards Urban Sustainability’. Geography, Environment, Sustainability 8(4): pp. 64–81.

The WHO/UNICEF Joint Monitoring Programme (JMP)’s definition of basic drinking water is: ‘drinking water from an improved source, provided collection time is not more than 30 minutes for a roundtrip including queuing’. Improved drinking water sources are ‘those which, by nature of their design and construction, have the potential to deliver safe water’.

Cross-country data over time on WASH progress became available in the twenty-first century, and shows huge disparities across countries. WASH provision in the twenty-first century presents different challenges from the ones that were found in the ‘sanitation revolution’. Rapid urbanization in low- and middle-income countries requires increasing investments to build water treatment plants, sewage systems, and guaranteed access to safe drinking water. Many countries do not have the resources—financial, technological, institutional—or political support to finance large infrastructure works. Figure 6 shows the asymmetry in access to basic drinking water for a sample of countries. High-income countries such as Germany have 100% coverage, and the rest of the countries have made progress since 2000. Still, there are serious coverage problems in several countries. There are even countries where coverage is decreasing, like the Democratic Republic of Congo, for example, due to wars, natural disasters, and political unrest. In other countries where there has been an improvement, coverage is still low, endangering many lives and harming young children disproportionately.

The WHO/UNICEF JMP’s definition of basic sanitation is the ‘use of improved facilities which are not shared with other households’. Improved facilities are those designed to hygienically separate excreta from human contact. However basic sanitation is not considered to be a safely managed sanitation service. For it to be considered as safely managed, in addition to using improved sanitation facilities which are not shared with other households, the excreta produced should either be: (1) treated and disposed of in situ, (2) stored temporarily and then emptied and treated off-site, or (3) transported through a sewer with wastewater and then treated off-site.

Access to sanitation has also improved, but at different rates. Figure 7 shows the percentage of a country’s population with access to basic sanitation. The situation has improved significantly in countries such as China, Indonesia, India, and Brazil. Unfortunately, progress remains very slow or has even stagnated for many low-income countries. On top of the potential for environmental hazards and effects on health, poor sanitation reduces welfare, reduces school attendance, and increases the risk of sexual assault on women, due to their need to go to remote rural areas to practice OD.

This line chart shows the share of population with access to basic drinking water (in percentages) from 2000 to 2022 across 19 countries. High-income countries (namely Germany, the UK, and the USA) maintain access levels close to or at 100% throughout. Others such as China, Vietnam, and Brazil show steady improvements, converging towards universal access by 2022. India and Indonesia also make substantial gains, moving from mid-range levels (around 70%) to over 90%. On the other hand, countries like Somalia, the Democratic Republic of Congo, and Angola start with the lowest access and experience slower progress, highlighting persistent disparities in water infrastructure and delivery.
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Figure 6 Percentage of a country’s population with access to basic drinking water (2000–2022).

Author’s elaboration based on WHO/UNICEF Joint Monitoring Programme, 2024.

The chart illustrates significant progress in sanitation access, with large disparities in starting points and trajectories among countries. It shows the share of the population with access to basic sanitation (in percentages) from 2000 to 2022 across 14 countries. The USA, UK, and Germany (lines at the top) maintain universal access near 100% throughout the period. China and India demonstrate the most rapid increases: China rises from around 45% to near-universal coverage, while India climbs from below 20% to over 70%. Countries like Bolivia, Haiti, and Tanzania start with lower access and make modest gains not reaching 50%.
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Figure 7 Percentage of a country’s population with access to basic sanitation (2000–2022).

Author’s elaboration based on WHO/UNICEF JMP, 2024.

The WHO/UNICEF JMP’s definition of open defecation is ‘the practise of defecating in fields, forests, bushes, bodies of water, or other open spaces’.

Figure 8 shows the percentage of people in a country who still practice open defecation (OD). Despite the reductions observed in some countries, OD rates in many low-income countries (such as Nigeria) are still very high and have not significantly improved since 2000. Also, compared to other types of household sanitation, OD practices are the ones that have the most potential for environmental contamination, aiding the spread of diseases such as cholera and dysentery. This situation worsens in rural areas, where the population is generally less dense but water is often contaminated with faecal pathogens due to poorer sewage management systems, and where the practice of open defecation is more prevalent.

The line chart illustrates global progress in reducing open defecation, with varied starting points and rates of improvement across countries. It shows the share of the population practising open defecation (in percentages) across 14 countries from 2000 to 2022. India (black line) shows the steepest decline, from over 90% in 2000 to below 20% by 2022. Other countries such as Bolivia, Indonesia, and Nigeria show moderate declines from higher initial levels, while countries like the UK, USA, and Germany remain at or near 0% throughout the period.
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Figure 8 Percentage of a country’s population that practise open defecation (2000–2022).

Author’s elaboration based on WHO/UNICEF JMP, 2024.

To sum up, by 2022, 57% of the global population had access to a safely managed sanitation service. But over 1.5 billion people do not yet have access to basic sanitation services such as private latrines, and over 400 million still practice open defecation. And in 2020, 44% of household wastewater globally was discharged without safe treatment.

Question 2 Choose the correct answer(s)

The ‘sanitary revolution’ that started in the 1850s was facilitated by which of the following factors?

  • urbanization
  • technological change
  • within-country inequalities in healthcare coverage
  • changes in philosophical and scientific thinking
  • Rapidly growing urban areas had higher demand for better sanitation services and water provision, due to greater prevalence of disease outbreaks and fires.
  • There were improvements in the methods used to supply water and dispose of human waste, including steam engines, metal piping, and water chlorination.
  • It is true that there are (and were) inequalities in healthcare coverage within countries, but that alone did not facilitate the sanitary revolution.
  • The Enlightenment introduced the idea that societies could improve their well-being by reforming their environment, and the idea that thinking should be based on observing evidence.

Exercise 1 Sanitation and childhood mortality rates

Choose three countries from Figures 6 to 8.

  1. For your chosen countries, download the following data:
    • Choose one measure of sanitation from the World Health Organization’s ‘Water, sanitation and hygiene’ web page. The sanitation measures are listed under the ‘Related Indicators’ heading. To download the data, click on this measure, select the ‘Data’ tab, then right-click the ‘Export data in CSV format’ option to save the data file.
    • Child mortality rates from Our World in Data. To download the data for your countries only, go to the ‘Child mortality rate’ chart and use the ‘Edit countries and regions’ option to select your chosen countries. Once your chosen countries are shown in the chart, select the download icon at the bottom-right corner, select the ‘Data’ tab, then ‘Download displayed data’.
  2. Plot one line chart per country, showing the sanitation measure and child mortality rates for all years where data for both variables is available. (If the two variables have very different ranges, try using a secondary vertical axis or separate charts.) For the sanitation measure, if separate data for rural and urban areas is available, plot a different line for each type of area.
  3. Discuss the similarities and differences between your charts from Question 2. How are changes in sanitation related to child mortality rates?

  1. Ido Badash, Nicole P. Kleinman, Stephanie Barr, et al. 2017. ‘Redefining Health: The Evolution of Health Ideas from Antiquity to the Era of Value-Based Care’. Cureus 9(2): e1018. ↩

  2. Emanuel, Ezekiel J. 2020. Which Country Has the World’s Best Health Care? Public Affairs. ↩

  3. United Nations. 2023. The Sustainable Development Goals Report 2023: Special Edition. ↩

  4. Roy, Tirthankar. 2021. ‘Water, Climate, and Economy in India from 1880 to the Present’. Journal of Interdisciplinary History 51(4): pp. 565–594. ↩