Twice in three years – at its 75th anniversary and again this July at the Constitution’s 80th – the World Health Oganization (WHO) has told the official story of what it has achieved. Twice, water, sanitation, air, chemicals and climate have been left out. The former head of WHO’s environmental health programme argues this is not a curatorial slip but institutional amnesia – and that the organization must correct the record.

On 24 July, marking 80 years since the signing of the WHO Constitution, the Director-General published a commemorative essay, “80 years strong: the WHO Constitution.” It is a graceful tribute to the founders – Parran, Sze, Štampar, Chisholm – and it declares, movingly, that “the Constitution remains our compass.”

Follow that compass to the page WHO itself links as related reading: the organization’s official timeline of public health milestones, curated for the 75th anniversary in 2023 and still presented today as the record of “some of the most memorable successes.” 

I have counted its entries many times, always with the same disbelief. There are roughly 70. Smallpox eradication is there, as it must be; polio, tobacco control, essential medicines, Alma Ata, the malaria vaccine – all rightly celebrated. 

But search all 70 for the words that defined public health for most of its existence – water, sanitation, air, chemical safety, climate – and you search in vain. The sole environment-touching entry in the entire timeline is the 2022 “One Health” memorandum among four agencies.

So, the record now stands doubly confirmed. At 75, WHO wrote seven decades of environmental health out of its history. At 80, invited to look again, it pointed straight back to the same erasure – in an essay that even honours Ludwik Rajchman and Raymond Gautier of the League of Nations Health Organisation without a single word about what that organisation actually did. 

I directed WHO’s environmental health programme (as director of the environmental health division in 1986, and executive director of Health and Environment from 1993 to 1998) in the years when the organization carried this field to the centre of the world stage.

But I do not write to defend my own era: the achievements that came after my time are among the most consequential things WHO has ever done, and they have been erased alongside it. An organization that cannot remember what it has achieved cannot defend it, fund it, or repeat it. 

Older than WHO itself

The omission wounds because environmental health is not a late addition to international health cooperation. It is its ancestor. As Jamie Bartram and colleagues documented in their authoritative 2014 history of global water and sanitation monitoring, the League of Nations Health Organization was publishing recommendations and collecting international data on drinking water and sanitation as early as 1930, under its rural hygiene programme. Monitoring that, in their words, “shapes awareness of countries’ needs and informs policy.” 

The great intergovernmental rural hygiene conferences of the 1930s, in Europe and Asia, treated safe water, housing, waste disposal and vector control as the very substance of health work.

WHO’s founders knew this inheritance and wrote it into law. Article 2 of the Constitution, whose 80th birthday we have just celebrated, makes it a core function of the organization to promote improved nutrition, housing, sanitation, working conditions and “other aspects of environmental hygiene.” 

The drafters put the environment into WHO’s legal DNA in 1946. Their successors could not find room for it 70 milestones in 2023 – nor in the birthday tribute to the Constitution itself in 2026.

When WHO put pipes in the ground

There is a generation of WHO staff – mine, and the one before – for whom the organization was not only a normative agency but an operational one, with mud on its boots. 

From the late 1950s WHO ran a global community water supply programme and posted sanitary engineers into ministries and municipal waterworks across the developing world. 

Working with UNDP and the World Bank, WHO teams conducted pre-investment studies and helped draw up master plans for water supply, sewerage, drainage, and water resources management for fast-growing cities – plans that unlocked hundreds of millions of dollars in investment and shaped infrastructure that still serves tens of millions of people. 

WHO issued guidance on wastewater reuse in agriculture, on water resources development and vector control engineering, and kept sanitary watch over ports and airports.

That operational tradition culminated in the International Drinking Water Supply and Sanitation Decade of 1981–1990, for which WHO was a lead technical agency hosting its secretariat– an unprecedented mobilization that extended services to hundreds of millions and created the monitoring machinery the world relies on to this day. 

The health dividend is written into WHO’s own anniversary timeline without being recognized for what it is: the 1978 entry records that annual diarrheal deaths in children under five fell from an estimated 4.6 million in 1980 to under 365 000 by 2019 – a 92% reduction achieved despite a 70% larger world population. 

Oral rehydration therapy rightly shares that entry, but no child is rehydrated out of repeated infection from filthy water and poor sanitation. The largest share of that curve belongs to taps, latrines and hygiene – the words the timeline will not say.

The quiet power of norms: Water

If the operational era has been forgotten, the normative achievements have been erased while still in active service – which is stranger still. WHO published its first international standards for drinking water in 1958, with new editions in 1963 and 1971, then transformed them into the Guidelines for Drinking-water Quality editions in 1983–84, 1993–97, 2004 and 2011, kept continuously current through rolling revision since 1995, with addenda to the fourth edition in 2017, 2022 and 2026. 

The 2004 third edition introduced the Water Safety Plan, the catchment-to-consumer risk-management framework now written into national regulations and utility practices worldwide.

Few products of any international organization have a comparable claim on daily life: when almost any government on Earth sets a legal limit for arsenic, lead, nitrate or microbial contamination in drinking water, the number it writes into law traces back to Geneva. Nearly seventy years of unbroken, science-driven protection of billions of consumers – not a milestone, apparently.

The quiet power of norms: Air

The same is true of the air we breathe. WHO has worked on air pollution since its first expert committees of the 1950s. I had the privilege of serving as WHO’s first long-term air quality management adviser to the government of the Republic of Korea.

From the 1970s, WHO coordinated global urban air quality monitoring with the UN Environment Programme (UNEP) – decades of measurement that made the problem visible long before it was fashionable.

In 2014, WHO published the estimates that changed the global conversation: around seven million premature deaths a year attributable to air pollution, making it the world’s largest single environmental health risk.

Its ambient air quality database now covers thousands of cities, and its 2014 indoor fuel-combustion guidelines confront the household smoke that still shrouds the roughly two billion people cooking with polluting fuels.

Then, in September 2021, came one of the most consequential normative acts in WHO’s history: the updated Global Air Quality Guidelines.  Acting on 15 years of accumulated evidence, the annual safety guideline for fine particulate matter (PM2.5) was halved from 10 to 5 µg/m³, the 24-hour value cut from 25 to 15, and the nitrogen dioxide guideline slashed by 75%, from 40 to 10.

Medical and public health societies worldwide jointly called the new guidelines “ambitious,” reflecting “the large impact that air pollution has” on global health.

They instantly became the benchmark against which every government’s air is judged – and the judgement is damning: some 99% of humanity breathes air exceeding them. These guidelines reshaped clean-air law from Brussels to Beijing. The timeline does not mention them.

The years I answer for

I will state my own era only briefly, because my argument is not about it. In 1989, Director-General Hiroshi Nakajima decided to make health and environment one of WHO’s key programme priorities – at a moment when, as I have often recalled, health was almost absent from the sustainability movement then gathering toward the 1992 Rio Earth Summit.

WHO’s answer was the independent Commission on Health and Environment, whose 1992 report, Our Planet, Our Health, put human health into the Rio agenda – into the Rio Declaration and Agenda 21.

Article 1 of the Rio Declaration states: “Human beings are at the centre of concerns for sustainable development. They are entitled to a healthy and productive life in harmony with Nature” – this is even more valid now as it was then.

The commission assessed how health is affected through its four technical panels – on food and agriculture; energy; industry; and urbanisation – and provided recommendations for strategies and actions to protect and promote health.

It already raised concerns about the changing climate due to CO2 emissions from fossil energy. As a consequence, in order to assess the potential health effects of climate change, an expert committee meeting was convened in 1989. Its report published by WHO contains information which describes scenarios which the world is now facing as a grim reality. 

Through the International Programme on Chemical Safety (IPCS) founded with the International Labour Organization (ILO) and UNEP in 1980, WHO provided comprehensive scientific understanding and technical support in the field of chemical safety. Its Environmental Health Criteria documents helped member states to set safety standards and laws to address the growing concern over environmental hazards. 

The IPCS INTOX project, led by Dr John Haines, brought together more than 100 specialists in poison control and related fields. It developed information for diagnosis and treatment; common terminology and formats for recording toxic exposures; information-management tools; training materials; and professional networks connecting poison centres and toxicologists across borders.

INTOX worked on antidotes, the harmonization of poisoning case data and preparedness for major chemical incidents. The cumulative human consequence cannot be calculated with precision, but there is little doubt that the centres, laboratories, information and professional networks INTOX helped to create, have contributed to saving many thousands of lives.

Decades later, WHO’s own quantifications were vindicated by Dr Nakajima’s priority: by the organization’s estimates, avoidable environmental factors are linked to roughly 13 million deaths every year–almost one in four of all deaths on Earth. There is no larger field of prevention in existence, and no field of prevention less visible in WHO`s account of its own history.

What came after me proves the point

Here is what the anniversary texts omitted – and it is essential that nearly all of it happened after I retired. This is not nostalgia for a vanished programme; environmental health produced some of WHO’s most transformative work of the 21st century, and it is producing it still today.

Monitoring 

The WHO/UNICEF Joint Monitoring Programme, tracking water and sanitation since 1990, did something in 2008 that few UN publications have ever done: it changed the world’s conversation.

Its report for the International Year of Sanitation, Progress on Drinking Water and Sanitation – Special Focus on Sanitation, introduced the now-universal “ladder” of service levels and, for the first time, put a global number on open defecation – nearly 1.2 billion people, among 2.5 billion without improved sanitation.

WHO’s own announcement called it “the riskiest sanitary practice of all.” Counting it dragged a taboo into the light of policy: India’s Swachh Bharat and dozens of national campaigns are unthinkable without that number, and the Sustainable Development Goals now carry an explicit target to end the practice. The numbers moved – 1.2 billion in 2008, 946 million by 2015, 354 million by 2024.

The same machinery told the world in 2012 that the Millennium Development goal (MDG) drinking-water target had been met five years early, and reports today that 961 million people gained safely managed drinking water between 2015 and 2024, lifting coverage from 68% to 74% – while insisting, with the honesty good monitoring demands, that 2.1 billion still lack it and that open defecation in low-income countries remains four times the global average. If a vaccine had driven curves like these, they would headline the anniversary page.

Climate 

From those first assessments in my era, WHO’s climate and health work grew into a World Health Assembly resolution in 2008, then into country support across the globe for vulnerability assessments, national adaptation plans for health, and climate-resilient health systems.

These in turn culminated in the Alliance for Transformative Action on Climate and Health, through which more than 100 countries have committed to climate action for health.

Health now features as a priority in 91% of countries’ Nationally Determined Contributions (NCDs) under the Paris Agreement. At COP30 in Belém, WHO and Brazil drove a global Health Action Plan.

The programme has achieved something my generation could scarcely have imagined: accreditation of WHO to the Green Climate Fund, making the organization a direct implementing entity for climate finance in a sector on a starvation diet – an estimated 2% of adaptation funding and just 0.5% of multilateral climate finance.

“Climate crisis is a health crisis, not hypothetically in the future, but here and now “, WHO Director-General Tedros Adhanom Ghebreyesus said recently.

Water safety planning revolution 

Add the water safety planning revolution, embedded in national law, the burden-of-disease machinery behind the 13-million-deaths estimate, the 2018 housing and sanitation guidelines, the air quality estimates published for nearly every country – and the pattern is undeniable.

This is a continuous, century-long, still-accelerating current of achievement running from the League of Nations rural hygiene surveys of 1930 to a Green Climate Fund accreditation in 2026. The anniversary texts overlooked all of it.

Why does it matter? 

Why do anniversary webpages matter this much? Because they are the organization telling member states, donors, young staff and itself what it believes it is for.

Budgets follow stories; careers follow stories. When WHO’s official self-portrait contains 70milestones and no water, no sanitation, no air, no chemicals and no climate – and when the 80th-anniversary tribute renews the omission – every health minister weighing an environmental investment, every foundation officer drafting a strategy, and every young engineer deciding whether WHO is a place for her receives the same message: this is not what WHO considers memorable.

That message is false, and it is costly. It is also economically illiterate: WHO’s own analysis shows every $1 invested in water and sanitation returns roughly $4.30 in reduced health costs and productivity gains. And as Dr Campbell-Lendrum, who leads WHO’s climate and health work, said: “At an absolute minimum, every dollar that you invest gets you $4 back”. 

Prevention produces no cured patients to photograph – the children who never contracted cholera thank no surgeon – which is precisely why institutional storytelling must carry it.

I do not believe anyone sat down intending to erase this history. That is the problem. The omission passed through drafting, review and approval at every level, twice, in exercises explicitly designed to showcase achievement – and no one senior enough noticed or objected.

A lapse of this scale, on this subject, in the century of climate disruption, is not an editorial detail. It is evidence of how far environmental health has slipped from the centre of WHO’s institutional self-understanding.

What the new WHO DG needs to correct 

WHO’s member states will soon choose the organization’s next Director-General – a leader who will govern in the century of climate disruption, polluted air, water insecurity and chemical proliferation, when the environmental determinants of health will not be one programme among many but the terrain on which all health outcomes are won or lost.

Let the correction begin simply. Amend the milestones timeline publicly to include what this article has named – from the League’s rural hygiene programme to the Green Climate Fund.

Protect and fund the normative crown jewels – the drinking-water and air quality guidelines, and the monitoring programmes – as core functions, not discretionary extras.

Place the environmental determinants of health at the heart of the next General Programme of Work, where the Constitution’s drafters put them in 1946.

The sanitary engineers of the 1960s, the guideline scientists, the monitoring statisticians and the climate-health pioneers asked for little recognition in their lifetimes; many are gone.

The least their organization owes them – and the most useful thing it can do for the billions still drinking unsafe water and breathing deadly air – is to remember out loud that this work is not a footnote to WHO’s story. For over 100 years, it has been the story.

Wilfried Kreisel directed WHO’s Division of Environmental Health (1986–1993) and was Executive Director for Health and Environment (1993–1998). He was Scientific Secretary of the WHO Commission on Health and Environment, convened WHO’s first expert consultation on climate change and health in 1989, and later headed the WHO offices in Brussels and Kobe.

Image Credits: Abir Abdullah / Climate Visuals, WHO 75th anniversary timeline., Source: WHO GDWQ prefaces., WHO/UNICEF JMP 2008, 2015, 2025., WHO/UNICEF JMP 2025., WHO (2026)..