Half of the world's 8 billion people still lack adequate access to safe water, sanitation and hygiene, causing 1.4 million preventable deaths each year, says a new study by the World Health Organization (WHO).
More than three-quarters of all deaths attributable to deficiencies in these essential services (grouped under the acronym Wash) occur in Africa and South-East Asia, with 510,000 and 593,000 deaths, respectively, compared to 33,000 deaths in the European region.
Diarrhoeal diseases accounted for the largest share of the burden attributable to Wash, with more than one million deaths, and the second largest contributor was acute respiratory infections due to inadequate hand hygiene, which was linked to 356,000 deaths.
Although 89% of deaths occurred in low- and lower-middle-income countries, high-income countries are also at risk, as 18% of their diarrhoeal disease burden could be prevented with better hand hygiene practices.
Among children under five, unsafe Wash was responsible for 395,000 deaths, accounting for 7.6 % of all deaths in this age group, including 273,000 deaths from diarrhoea and 112,000 deaths from acute respiratory infections.
These diseases are the two leading infectious causes of death in children under five worldwide.
The report, an update to the 2019 study "Burden of disease attributable to unsafe drinking water, sanitation and hygiene," cautions that its figures estimate four health outcomes for which data were available to quantify the impact, but the true burden is likely to be much higher.
Maria Neira, director of the WHO's Department of Environment, Climate Change and Health, said in launching the report that "we have seen improvements in Wash service levels over the past 10 years, but progress is uneven and insufficient."
"With increasing Wash-related health risks already seen today through conflict, the emergence of antimicrobial resistance, the re-emergence of cholera outbreaks and the long-term threats of climate change, the imperative to invest in this area is stronger than ever," Neira said.
The WHO argues that the health impacts of unsafe washing are wide-ranging and go beyond illness, affecting social and mental well-being.
In addition, climate change is likely to exacerbate many diseases and related risks, which are not fully captured in current estimates.
To reduce the burden of disease attributable to Wash, WHO urges governments to take action with support from UN agencies, multilateral partners, the private sector and civil society organisations.
First, radically accelerate action to make safe Wash a reality for all, as outlined in the Sustainable Development Goals (SDGs) of the UN 2030 Agenda. SDG 6, Ensure availability and sustainable management of water and sanitation for all, targets 6.1 to Achieve universal and equitable access to safe and affordable drinking water for all by 2030.
Target 6.2 includes Achieving access to adequate and equitable sanitation and hygiene for all and ending open defecation, which is still a practice for more than 800 million people.
WHO stresses the need to focus efforts on the poorest and most disadvantaged, as the burden of disease is largely due to inadequate access in low- and middle-income countries, and national estimates of access to Wash often mask disparities within countries. Access to Wash services are often lower among rural populations and lower socio-economic groups. Even in high-income countries, where access to safe water and sanitation services is generally high, certain marginalised communities are underserved and face higher risks.
Finally, it is recommended that national monitoring systems be adapted to improve data on population exposure to safely managed services, as data on higher levels of Wash services remain scarce in many countries.