Global Challenges

Clear, source-backed overviews of the world’s hardest problems: how big each one is, where it hits hardest, what already works, what blocks progress and which questions remain open.

Every figure links to a primary source. We mark what is proven, what is still being tested and what nobody knows yet.

challenges: 100
world maps: 78
cited sources: 585

All 100 challenges

Water & Sanitation · SDG 6Improving
Clean Water for Everyone
One in four people worldwide still cannot rely on drinking water that is on premises, available when needed and free from contamination.
2.1 billionPeople without safely managed drinking water (2024)
Outcome
Moderate
Solutions
High
Reach
Moderate
Health · SDG 3Mixed
Alzheimer's Disease and Dementia
Dementia affects tens of millions of people and their families, most cases are never formally diagnosed, and the treatments available today can slow early Alzheimer's disease only modestly.
57 millionPeople living with dementia (2021)
Outcome
Low
Solutions
Moderate
Reach
Low
Environment · SDG 13Worsening
Limiting Global Warming
Human activity has already warmed the planet by well over 1 °C, and greenhouse gas emissions are still near record levels instead of falling.
1.43 °CGlobal temperature rise above pre-industrial (2025)
Outcome
Low
Solutions
High
Reach
Moderate
Education · SDG 4Stalling
Quality Education for Every Child
About one in six children and young people of school age is not in school, and most 10-year-olds in low- and middle-income countries are estimated to be unable to read a simple text.
273 millionChildren and youth out of school (2024)
Outcome
Moderate
Solutions
High
Reach
Low
Health · SDG 3Worsening
Antibiotics That Keep Working
Bacteria are becoming resistant to the antibiotics we rely on faster than new treatments arrive, and resistant infections already play a part in millions of deaths each year.
1.14 millionDeaths directly attributable to bacterial AMR (2021)
Outcome
Low
Solutions
Moderate
Reach
Low
Poverty · SDG 1Stalling
Ending Extreme Poverty
About one in ten people worldwide lives on less than $3.00 a day, and after decades of rapid decline the global rate has fallen only slowly since the COVID-19 pandemic.
824 millionPeople in extreme poverty (2024)
Outcome
Moderate
Solutions
High
Reach
Low
Food · SDG 2Mixed
Zero Hunger
About one in thirteen people in the world does not regularly get enough food to live a healthy, active life, and almost one in four children under five is too short for their age because of chronic undernutrition.
645 millionPeople facing chronic hunger (2025)
Outcome
Low
Solutions
Moderate
Reach
Low
Health · SDG 3Stalling
Ending Malaria
Malaria is preventable and treatable, yet it still causes hundreds of thousands of deaths a year, mostly among young children in Africa, and progress has stalled since 2015.
610,000Estimated malaria deaths (2024)
Outcome
Low
Solutions
Moderate
Reach
Moderate
Health · SDG 3Stalling
Every Child Survives Their Fifth Birthday
The world has cut the child death rate by about 60% since 1990, but 4.9 million children still die before their fifth birthday each year, mostly from preventable or treatable causes, and progress has slowed sharply since 2015.
4.9 millionChildren who died before age five (2024)
Outcome
Moderate
Solutions
High
Reach
Moderate
Environment · SDG 3Mixed
Clean Air to Breathe
Almost everyone breathes air that is dirtier than WHO's guideline, and outdoor and household air pollution together are among the largest causes of early death worldwide.
7.9 millionDeaths linked to air pollution (2023)
Outcome
Moderate
Solutions
Moderate
Reach
Moderate
Energy · SDG 7Stalling
Energy for Everyone
About nine in ten people worldwide now have electricity at home, but progress has stalled: 655 million people still have none, and about a quarter of humanity still cooks mainly with smoky, polluting fuels.
655 millionPeople without electricity (2024)
Outcome
Moderate
Solutions
High
Reach
Moderate
Health · SDG 3Stalling
Safe Childbirth for Every Mother
The global maternal mortality ratio fell by 40% between 2000 and 2023, but an estimated 260,000 women still died from complications of pregnancy and childbirth in 2023, most of them from preventable causes, and progress has slowed since 2016.
260,000Women who died from maternal causes (2023)
Outcome
Moderate
Solutions
High
Reach
Moderate
Health · SDG 3Mixed
Ending Tuberculosis
Tuberculosis is preventable and curable, yet it still kills more than a million people a year, and the decline since 2015 has been far too slow to meet global targets.
10.7 millionPeople who fell ill with TB (2024)
Outcome
Moderate
Solutions
Moderate
Reach
Moderate
Health · SDG 3Mixed
Ending AIDS
Treatment now lets people living with HIV live long, healthy lives and stops onward transmission, yet 1.2 million people acquired HIV in 2025, the 2025 global targets were missed and cuts in international funding are disrupting services.
41.0 millionPeople living with HIV (2025)
Outcome
Moderate
Solutions
High
Reach
Moderate
Health · SDG 3Mixed
Mental Health Care for Everyone
Nearly one in seven people worldwide lives with a mental disorder, yet most never receive effective care, because mental health services remain underfunded, understaffed and concentrated in high-income countries.
1.2 billionPeople living with a mental disorder (2023)
Outcome
Low
Solutions
Moderate
Reach
Low
Health · SDG 3Mixed
Safe Roads for Everyone
Road crashes kill more than a million people a year, mostly in low- and middle-income countries, and more than half of those killed are walking, cycling or riding a motorcycle; death rates are falling, but far too slowly to halve road deaths by 2030.
1.16 millionPeople killed in road crashes (2025)
Outcome
Low
Solutions
High
Reach
Low
Health · SDG 3Mixed
Ending Neglected Tropical Diseases
Neglected tropical diseases are a diverse group of infections and conditions that mainly affect poor communities in the tropics; the number of people who need treatment has fallen by more than a third since 2010, but well over a billion still do.
1.41 billionPeople requiring interventions against NTDs (2024)
Outcome
Moderate
Solutions
Moderate
Reach
Moderate
Health · SDG 3Mixed
Ready for the Next Pandemic
COVID-19 showed how costly an unprepared world is; since then governments have strengthened the international health rules, but average country capacity has stopped improving, aid for health is falling and the new Pandemic Agreement is not yet open for signature.
22.1 millionExcess deaths linked to COVID-19, 2020–2023 (2023)
Outcome
Low
Solutions
Moderate
Reach
Low
Water & Sanitation · SDG 6Improving
Safe Toilets for Everyone
In 2024, 3.4 billion people did not have a private toilet whose waste is safely managed, 354 million had no toilet at all, and 1.7 billion had no place at home to wash their hands with soap and water.
3.4 billionPeople without safely managed sanitation (2024)
Outcome
Moderate
Solutions
Moderate
Reach
Moderate
Environment · SDG 15Worsening
Halting Biodiversity Loss
Wild species and the ecosystems they form are declining on land, in fresh water and at sea: monitored vertebrate populations shrank by 73% on average between 1970 and 2022, and 49,505 of the species assessed for the IUCN Red List are threatened with extinction.
73%Average decline in monitored wildlife populations (2022)
Outcome
Low
Solutions
Moderate
Reach
Low
Environment · SDG 12Worsening
Ending Plastic Pollution
The world now produces around 475 million tonnes of plastic a year but recycles less than a tenth of its plastic waste, and tens of millions of tonnes escape into the environment each year, much of it burned in the open or carried by rivers towards the sea.
475 million tonnesPlastics produced worldwide (2022)
Outcome
Low
Solutions
Moderate
Reach
Low
Environment · SDG 15Mixed
Stopping Deforestation
Deforestation has slowed since the 1990s, but around 11 million hectares of forest are still cleared every year, mostly in the tropics and mostly for farming, and the world is far off track to end it by 2030.
10.9 million haForest cleared each year (2025)
Outcome
Moderate
Solutions
Moderate
Reach
Low
Environment · SDG 6Worsening
Saving the World's Wetlands
Wetlands regulate water, buffer floods, provide food and store large amounts of carbon, yet about a fifth of their area has been lost since 1970 and the loss has not stopped.
411 million haWetland area lost since 1970 (2020)
Outcome
Low
Solutions
Moderate
Reach
Low
Food · SDG 12Stalling
Wasting Less Food
About 13% of the world's food is lost after harvest before it reaches shops, and almost a fifth of the food available to consumers is wasted in shops, restaurants and homes, using up land, water and money and contributing 8 to 10% of human-caused greenhouse gas emissions.
1.05 billion tonnesFood wasted in retail, food service and households (2022)
Outcome
Low
Solutions
Moderate
Reach
Low
Housing · SDG 11Worsening
A Home for Everyone
Homelessness has risen in most countries that measure it and more than 1.16 billion people live in slums or informal settlements, while approaches known to help people find and keep a home, such as Housing First and emergency rent help, reach too few.
2.6 million+People reported as homeless across OECD countries (2026)
Outcome
Low
Solutions
Moderate
Reach
Low
Human Rights · SDG 8Improving
Ending Child Labour
Nearly 138 million children, almost 8% of all children aged 5 to 17, were in child labour in 2024, down from 246 million in 2000, but the 2025 deadline to end it has been missed and progress would have to be 11 times faster to end it by 2030.
138 millionChildren in child labour (2024)
Outcome
Moderate
Solutions
Moderate
Reach
Low
Human Rights · SDG 5Mixed
Ending Violence Against Women and Girls
Nearly one in three women worldwide has experienced violence from a partner or sexual violence from someone else, a share that has barely changed since 2000, while child marriage and female genital mutilation are declining but not fast enough to end by 2030.
840 millionWomen who have experienced partner or sexual violence (2023)
Outcome
Low
Solutions
Moderate
Reach
Low
Human Rights · SDG 10Mixed
Safety for People Forced to Flee
About 1 in 70 people worldwide have been forced from their homes by conflict, violence or persecution; most stay in poorer neighbouring countries for years, and the support that helps them rebuild their lives shrank sharply in 2025.
117.8 millionPeople forcibly displaced (2025)
Outcome
Low
Solutions
Moderate
Reach
Low
Human Rights · SDG 8Worsening
Ending Modern Slavery
Nearly one in every 150 people in the world was held in forced labour or a forced marriage in 2021, and the latest global estimates show the number rising rather than falling.
49.6 millionPeople in modern slavery (2021)
Outcome
Low
Solutions
Moderate
Reach
Low
Technology · SDG 9Improving
Internet Access for Everyone
Three in four people now use the Internet, but 2.2 billion remain offline, and for most of them the obstacle is no longer a missing signal but the cost of phones and data, limited skills and other barriers to use.
2.2 billionPeople offline (2025)
Outcome
Moderate
Solutions
Moderate
Reach
Moderate
Human Rights · SDG 16Mixed
A Family for Every Child
An estimated 5.4 million children were living in institutions in 2015, and decades of research link institutional care to delays in growth, cognition and attention that moving into family care can partly reverse. Studies suggest that most children in so-called orphanages have a living parent.
5.4 millionChildren living in institutions (2015)
Outcome
Low
Solutions
Moderate
Reach
Low
Health · SDG 3Stalling
Every Child Vaccinated
Nine in ten infants now receive at least one routine vaccine, but 13.5 million still get none, measles is spreading again, and the global goal of halving the number of unvaccinated children by 2030 is seriously off track.
13.5 millionZero-dose children (2025)
Outcome
Moderate
Solutions
High
Reach
Moderate
Health · SDG 3Stalling
Health Care Everyone Can Afford
Most countries have widened access to health care since 2000, but in 2023 about 4.6 billion people were still not fully covered by essential health services, 2.1 billion faced financial hardship from paying for care in 2022, and progress has slowed markedly since 2015.
4.6 billionPeople not fully covered by essential services (2023)
Outcome
Moderate
Solutions
High
Reach
Moderate
Health · SDG 3Mixed
Surviving Cancer Wherever You Live
Cancer kills nearly 10 million people a year, and whether someone survives it depends heavily on where they live, because prevention, early diagnosis and treatment are far less available in poorer countries.
20.6 millionPeople newly diagnosed with cancer (2024)
Outcome
Moderate
Solutions
High
Reach
Low
Health · SDG 3Stalling
Healthy Hearts
Heart attacks, strokes and other cardiovascular diseases are the world's leading cause of death, and most of the 1.4 billion adults with high blood pressure, a key driver, do not have it under control.
19.8 millionDeaths from cardiovascular diseases (2022)
Outcome
Moderate
Solutions
High
Reach
Low
Health · SDG 3Worsening
Diabetes Care for All
The number of adults with diabetes has more than quadrupled since 1990, and most of the people affected live in low- and middle-income countries, where many are never diagnosed or treated.
589 millionAdults aged 20–79 with diabetes (2024)
Outcome
Low
Solutions
High
Reach
Low
Health · SDG 3Improving
A Tobacco-Free Generation
About 1.2 billion people still use tobacco, which kills more than 7 million people a year; adult use has fallen steadily since 2000, but too slowly to meet the 2025 reduction target, and e-cigarettes are drawing in millions of children.
1.2 billionPeople who use tobacco (2024)
Outcome
Moderate
Solutions
High
Reach
Moderate
Environment · SDG 14Mixed
Living Oceans
More than a third of the world's assessed marine fish stocks are fished faster than they can replenish, up from a tenth in 1974, while only about 10% of the ocean lies in protected or conserved areas.
35.5%Assessed marine fish stocks that are overfished (2021)
Outcome
Low
Solutions
High
Reach
Moderate
Water & Sanitation · SDG 6Mixed
Enough Water for People and Nature
In many river basins and aquifers, farms, industry and cities withdraw more fresh water than nature can renew, leaving less for people, food production and ecosystems in dry years and in the future.
17.6%Global level of water stress (2023)
Outcome
Low
Solutions
Moderate
Reach
Low
Environment · SDG 15Worsening
Healthy Land and Soil
Each year at least 100 million hectares of land lose part of their ability to grow food and support life, and the share of degraded land rose between 2015 and 2019 even as countries pledged to restore more than a billion hectares.
15.5%Share of land degraded (2019)
Outcome
Low
Solutions
Moderate
Reach
Low
Environment · SDG 11Mixed
Safe from Disasters
Floods, storms, earthquakes, droughts and heatwaves still kill tens of thousands of people and affect over 100 million every year; the death rate has fallen as early warning and preparedness have spread, but the number of people affected and the cost of disasters keep rising, and the poorest countries carry a disproportionate share.
41,000Average disaster deaths per year (2024)
Outcome
Moderate
Solutions
High
Reach
Moderate
Human Rights · SDG 16Improving
Every Birth Counted
About 150 million children under five, around 2 in 10, have never had their birth registered, and some 800 million people worldwide have no official proof of identity, most of them in sub-Saharan Africa and South Asia.
150 millionChildren under five without a registered birth (2024)
Outcome
Moderate
Solutions
High
Reach
Moderate
Human Rights · SDG 5Improving
Childhood, Not Marriage
In 2025 an estimated 18.5% of women aged 20 to 24 had been married or in a union before age 18, down from 22% in 2015, and although the decline has sped up, child marriage is still far from ending by the 2030 target.
18.5%Young women married before age 18 (2025)
Outcome
Moderate
Solutions
Moderate
Reach
Low
Poverty · SDG 8Stalling
Decent Work for Young People
One in five young people aged 15 to 24, about 257 million, were not in employment, education or training in 2025, young women at more than twice the rate of young men, and the ILO expects the share to keep rising slightly to 2027.
257 millionYoung people not in employment, education or training (2025)
Outcome
Low
Solutions
Moderate
Reach
Low
Poverty · SDG 8Improving
A Safe Place for Every Dollar
Four in five adults now have a bank or mobile money account, but 1.3 billion still have none, and many of those who do cannot save, borrow or cope with an emergency on affordable terms.
1.3 billionAdults without an account (2024)
Outcome
Moderate
Solutions
Moderate
Reach
Moderate
Human Rights · SDG 10Mixed
A World Built for Everyone
About one in six people worldwide has a significant disability, and inaccessible buildings, services, schools and workplaces, together with discrimination and the extra costs of disability, still leave many of them poorer, less healthy and less often employed than others.
1.3 billionPeople with a significant disability (2022)
Outcome
Low
Solutions
Moderate
Reach
Low
Human Rights · SDG 16Worsening
Peace and Protection for Civilians
More armed conflicts involving states were active in 2025 than in any year since 1946, and civilians bear much of the cost through deaths and injuries, hunger, displacement and attacks on the hospitals, schools and aid workers they depend on.
244,600Deaths in organized violence (2025)
Outcome
Low
Solutions
Moderate
Reach
Low
Human Rights · SDG 16Mixed
Honest Institutions
In the median country with data, about 17% of people who dealt with a public official in the past year paid a bribe or were asked for one, this share has stayed roughly stable in countries with comparable surveys, and the average score on the main perception index fell to 42 out of 100 in 2025.
17%People asked for or paying a bribe (2024)
Outcome
Low
Solutions
Moderate
Reach
Moderate
Human Rights · SDG 5Mixed
Equal Economic Opportunity for Women
Women have on average only about two-thirds of the legal rights of men in the economy, fewer than half of them work or seek work compared with almost three-quarters of men, and 708 million women are kept out of the labour force by care responsibilities.
About two-thirdsWomen's legal rights compared with men's (2025)
Outcome
Moderate
Solutions
Moderate
Reach
Low
Health · SDG 3Improving
Girls Choosing Their Future
The birth rate among girls aged 15–19 fell from 66.3 to 37.6 per 1,000 between 2000 and 2025, yet about 4.7 million babies were still born to mothers under 18 in 2024, and rates remain highest in sub-Saharan Africa.
37.6Births per 1,000 girls aged 15–19 (2025)
Outcome
Moderate
Solutions
Moderate
Reach
Moderate
Health · SDG 3Improving
No More Preventable Drownings
Drowning kills around 300,000 people a year, nine in ten of them in low- and middle-income countries and many of them children; the global death rate has fallen since 2000, but proven measures such as supervised childcare, barriers and swimming lessons still reach only a minority of countries.
300,000People who died from drowning (2021)
Outcome
Moderate
Solutions
High
Reach
Low
Health · SDG 3Mixed
Ending Viral Hepatitis
Hepatitis B can be prevented with a vaccine and hepatitis C can be cured with a short course of pills, yet together they still kill about 1.3 million people a year, mostly because few people are tested and treated.
1.3 millionDeaths from hepatitis B and C (2024)
Outcome
Moderate
Solutions
High
Reach
Low
Health · SDG 3Worsening
Stopping Dengue
Dengue, a viral infection spread by Aedes mosquitoes, has grown from about half a million reported cases in 2000 to a record of more than 14 million in 2024, and it is reaching places that have never had it before.
14.4 millionDengue cases reported to WHO (2024)
Outcome
Low
Solutions
Moderate
Reach
Low
Food · SDG 3Worsening
Healthy Food Environments
More than one billion people now live with obesity, and the rise is driven far more by what food is cheap, available and advertised than by individual choices, which is why most of the tools to change it are public policies.
1.1 billionPeople living with obesity (2024)
Outcome
Low
Solutions
Moderate
Reach
Low
Health · SDG 3Stalling
Less Harm from Alcohol
Alcohol caused an estimated 2.6 million deaths in 2019, 4.7% of all deaths worldwide; the death rate is falling, but consumption has barely changed, alcohol is becoming more affordable in most countries, and very few people with alcohol use disorders get treatment.
2.6 millionDeaths caused by alcohol each year (2019)
Outcome
Low
Solutions
High
Reach
Low
Health · SDG 3Mixed
The Last Steps to End Polio
Wild polio has been pushed back by more than 99% since 1988 and now survives only in Afghanistan and Pakistan, but transmission there persists, vaccine-derived outbreaks continue in dozens of countries, and the programme faces a funding shortfall in its final stretch.
52Wild poliovirus cases (2025)
Outcome
High
Solutions
High
Reach
Moderate
Water & Sanitation · SDG 6Mixed
Ending Cholera
Cholera is preventable and almost always treatable, yet the deaths reported to WHO in 2025 were the highest since 1999, concentrated in a few countries affected by conflict and lacking safe water and sanitation.
7,870Cholera deaths reported to WHO (2025)
Outcome
Low
Solutions
High
Reach
Low
Health · SDG 3Mixed
No One Dies in Pain
Around 73 million people a year live with serious suffering linked to illness that palliative care could ease, eight in ten of them in low- and middle-income countries, yet only a small minority receive such care and essential pain medicines such as oral morphine remain scarce in much of the world.
73.5 millionPeople with serious health-related suffering (2021)
Outcome
Low
Solutions
High
Reach
Low
Environment · SDG 14Worsening
Saving Coral Reefs
Ocean heat has become the main threat to coral reefs: the 2023–2025 global bleaching event exposed 84% of the world's reef area to bleaching-level heat stress, global hard coral cover has fallen, and 44% of reef-building coral species are now threatened with extinction.
84%Reef area hit by bleaching-level heat stress (2025)
Outcome
Low
Solutions
Moderate
Reach
Low
Environment · SDG 12Worsening
Electronics That Don't Poison
The world now throws away about 62 million tonnes of electrical and electronic equipment a year, less than a quarter of it is documented as properly collected and recycled, and much of the rest is dumped, landfilled or taken apart by hand in ways that expose workers and children to lead, mercury and other toxic substances.
62 million tonnesE-waste generated worldwide (2022)
Outcome
Low
Solutions
Moderate
Reach
Low
Water & Sanitation · SDG 6Stalling
Clean Rivers and Lakes
In 2024 only about 56% of the wastewater produced by households worldwide was safely treated, and in 2023 only 56% of the rivers, lakes and aquifers that countries monitor had good water quality, with little sign of improvement since monitoring began.
56%Household wastewater safely treated (2024)
Outcome
Low
Solutions
Moderate
Reach
Moderate
Environment · SDG 13Worsening
Safe from Extreme Heat
Extreme heat is estimated to cause about half a million deaths a year and puts billions of workers at risk; most of these deaths are preventable with warnings, cooling, shade and outreach to people most exposed, but protection reaches only part of the people who need it while dangerous heat becomes more frequent.
489,000Heat-related deaths each year (2019)
Outcome
Low
Solutions
Moderate
Reach
Low
Housing · SDG 11Mixed
A Decent Home in Every City
About one in four city residents worldwide, more than 1.16 billion people, live in slums and informal settlements without safe water, sanitation, enough space, a durable home or secure tenure, and their number grew by more than 130 million between 2015 and 2024.
1.16 billionPeople living in slums and informal settlements (2024)
Outcome
Low
Solutions
Moderate
Reach
Low
Poverty · SDG 10Mixed
Fairer Shares
Fewer countries are highly unequal than in the 1990s, but income and especially wealth remain concentrated at the top, both within countries and between rich and poor regions.
43 of 169Economies with high income inequality (2024)
Outcome
Moderate
Solutions
Moderate
Reach
Low
Poverty · SDG 1Mixed
A Safety Net for Everyone
For the first time just over half of the world's population receives at least one social protection benefit, but 3.8 billion people still have none, and in low-income countries fewer than one in ten are covered.
3.8 billionPeople without any social protection benefit (2023)
Outcome
Moderate
Solutions
High
Reach
Low
Food · SDG 2Mixed
Thriving Small Farms
Five in six of the world's farms are smaller than two hectares and together grow about a third of its food, yet many of the people who run them earn too little from farming to escape poverty or invest in coping with a changing climate.
608 millionFamily farms worldwide (2021)
Outcome
Low
Solutions
Moderate
Reach
Low
Human Rights · SDG 16Mixed
Childhoods Free from Violence
About 1.6 billion children, two in every three, regularly experience violent punishment by caregivers at home, yet only 15% of the world's children live where the law fully prohibits corporal punishment.
1.6 billionChildren who experience violent discipline at home (2024)
Outcome
Low
Solutions
Moderate
Reach
Low
Human Rights · SDG 16Stalling
Justice for All
An estimated 5.1 billion people, about two-thirds of humanity, cannot get fair and timely solutions to their legal problems, and nearly a third of the world's 11.6 million prisoners in 2024 were still waiting to be tried or sentenced.
5.1 billionPeople without meaningful access to justice (2019)
Outcome
Low
Solutions
Moderate
Reach
Low
Health · SDG 3Mixed
Ageing with Dignity
The number of people aged 60 and over passed 1 billion in 2020 and is heading for 2.1 billion by 2050, yet more than 165 million people above retirement age receive no pension, about one in six older people experience abuse each year, and only just over half of countries have a national long-term care policy.
165 million+People above retirement age with no pension (2023)
Outcome
Moderate
Solutions
Moderate
Reach
Low
Education · SDG 4Stalling
A Qualified Teacher in Every Classroom
UNESCO projects that the world needs 44 million additional primary and secondary teachers by 2030, while about one in five current teachers does not meet national minimum qualification standards.
44 millionAdditional teachers needed by 2030 (2022)
Outcome
Low
Solutions
Moderate
Reach
Low
Education · SDG 4Stalling
A Strong Start for Every Child
A quarter of children worldwide still start primary school without a year of organised learning, and an estimated 249 million children under five in low- and middle-income countries are at risk of not reaching their developmental potential.
75%Children in organised learning one year before primary school (2024)
Outcome
Low
Solutions
Moderate
Reach
Moderate
Food · SDG 2Mixed
Ending Child Stunting
Almost one in four children under five is too short for their age because of chronic undernutrition in the first years of life, and progress is too slow to halve that number by 2030.
150.2 millionChildren under five who are stunted (2024)
Outcome
Moderate
Solutions
Moderate
Reach
Low
Health · SDG 2Worsening
Reducing Anaemia
Anaemia affects nearly a third of the world's women of reproductive age and about two in five young children, and among women it has become more common, not less, since 2012.
30.7%Women aged 15–49 with anaemia (2023)
Outcome
Low
Solutions
Moderate
Reach
Moderate
Health · SDG 3Mixed
Stopping Deaths from Sepsis
Sepsis, the body's life-threatening reaction to an infection, was involved in almost a third of all deaths worldwide in 2021, and much of it could be prevented or treated in time.
21.4 millionSepsis-related deaths (2021)
Outcome
Low
Solutions
Moderate
Reach
Low
Health · SDG 3Mixed
Closing the Epilepsy Treatment Gap
Most people living with epilepsy could live without seizures on medicines that can cost a few dollars a year, yet in low-income countries about three in four of them are not treated.
about 50 millionPeople living with epilepsy (2024)
Outcome
Low
Solutions
High
Reach
Low
Health · SDG 3Improving
Preventing Suicide
Suicide claims hundreds of thousands of lives every year, most of them in low- and middle-income countries, yet it is preventable: a small set of tested public policies and timely support for people in crisis can save many lives.
727,000People who died by suicide (2021)
Outcome
Moderate
Solutions
Moderate
Reach
Low
Health · SDG 3Mixed
Preventing Drug Overdose Deaths
Nearly half a million people died from drug use in 2023, 29% more than a decade earlier; opioids cause most of these deaths, and although naloxone and opioid agonist treatment are well proven, only about one in 12 people with drug use disorders is in treatment.
Nearly 500,000People who died from drug use (2023)
Outcome
Low
Solutions
High
Reach
Low
Health · SDG 3Stalling
Safe Surgery for Everyone
An estimated 5 billion people cannot get safe, affordable surgical and anaesthesia care when they need it, at least 160 million needed operations go undone each year, and tens of millions of people face financial catastrophe because of what surgery costs them.
5 billionPeople without safe, affordable surgery (2015)
Outcome
Low
Solutions
High
Reach
Low
Health · SDG 3Mixed
Hearing Care for All
More than 1.5 billion people live with some hearing loss and about 430 million need rehabilitation for disabling hearing loss, yet most people who could benefit from a hearing aid do not have one, and many causes, from ear infections to loud noise, are preventable.
430 millionPeople who need rehabilitation for disabling hearing loss (2019)
Outcome
Low
Solutions
High
Reach
Low
Health · SDG 3Mixed
Ending Avoidable Blindness
About 1.1 billion people live with vision impairment, most of it preventable or treatable with cataract surgery or a pair of glasses, yet only about half of older adults who need cataract surgery get a good result from it and the 2030 coverage targets are far out of reach.
1.1 billionPeople with distance vision impairment or uncorrected near vision (2020)
Outcome
Moderate
Solutions
High
Reach
Moderate
Health · SDG 3Stalling
Oral Health for Everyone
Tooth decay and gum disease are largely preventable with fluoride and less sugar, yet they affect almost half of humanity, and most people live where basic oral health care is neither covered by health systems nor affordable.
3.7 billionPeople living with a main oral condition (2023)
Outcome
Low
Solutions
High
Reach
Low
Water & Sanitation · SDG 6Mixed
Menstrual Health and Dignity
Many girls and women still lack the materials, facilities, knowledge, pain relief and support they need during menstruation: in surveys from 44 countries, 15% had missed school, work or social activities during their last period, and only about one school in three had a bin for menstrual waste in girls' toilets.
15%Women and girls who missed activities during their last period (2023)
Outcome
Low
Solutions
Moderate
Reach
Low
Human Rights · SDG 5Mixed
Ending Female Genital Mutilation
More than 230 million girls and women alive today have undergone female genital mutilation, and although the share of adolescent girls affected fell from about 46% to 31% over three decades in the countries with data, the decline would need to be 27 times faster to end the practice by 2030.
230 million+Girls and women alive who have undergone FGM (2024)
Outcome
Moderate
Solutions
Moderate
Reach
Low
Human Rights · SDG 16Mixed
Ending Statelessness
At least 4.5 million people are recognised by no country as its nationals, and the true number is likely much higher because many stateless groups are never counted; most are members of minorities, and 24 countries still bar mothers from passing on their nationality on equal terms with fathers.
4.5 millionStateless people reported (2025)
Outcome
Low
Solutions
High
Reach
Low
Human Rights · SDG 16Worsening
Clearing Landmines and Explosive Remnants
Landmines and other explosive remnants of war killed or injured at least 6,279 people in 2024, nine in ten of them civilians, while clearance falls short of the 2025 goal, support for survivors shrinks and five European countries have left the treaty that bans antipersonnel mines.
6,279People killed or injured (2024)
Outcome
Low
Solutions
High
Reach
Moderate
Human Rights · SDG 16Improving
Reducing Violent Deaths
Intentional homicide kills several hundred thousand people a year, more than armed conflict and terrorism combined, and although the global rate has fallen since 2015, it is not falling fast enough to meet the goal of significantly reducing violent deaths by 2030.
5.1 per 100,000Global homicide rate (2024)
Outcome
Moderate
Solutions
Moderate
Reach
Low
Environment · SDG 14Worsening
Slowing Ocean Acidification
As the ocean takes up carbon dioxide from burning fossil fuels, its surface has become about 18% more acidic since 1985, and in 2025 ocean acidification was assessed as the seventh planetary boundary to be crossed, putting corals, shellfish and other shell-building life at risk.
8.04Global average surface ocean pH (2024)
Outcome
Low
Solutions
Moderate
Reach
Low
Environment · SDG 3Mixed
Ending Childhood Lead Poisoning
Lead harms children's brains at levels once thought safe, and a 2020 UNICEF and Pure Earth analysis estimated that around one in three children worldwide, up to 800 million, have blood lead levels at or above 5 µg/dL, the level at which WHO recommends finding and stopping the source.
Up to 800 millionChildren with blood lead at or above 5 µg/dL (2020)
Outcome
Moderate
Solutions
Moderate
Reach
Moderate
Environment · SDG 13Worsening
Adapting to Sea-Level Rise
Global sea level has risen about 10 cm since 1993 and the rate has roughly doubled, while some 896 million people live in the low-lying coastal zone; proven ways to adapt exist, but early warnings and adaptation finance reach only part of the people and places that need them.
4.75 mm a yearAverage rate of global sea-level rise, 2012–2025 (2025)
Outcome
Low
Solutions
Moderate
Reach
Low
Environment · SDG 13Worsening
Living with Extreme Wildfires
Fire is a natural part of many landscapes, but extreme wildfires are becoming more frequent and destructive, now cause about four in ten hectares of the world's tree cover loss and fill the air with smoke linked to an estimated 1.5 million premature deaths a year, while prevention and community fire management remain underfunded.
About 1.5 millionPremature deaths a year linked to fire smoke (2025)
Outcome
Low
Solutions
Moderate
Reach
Low
Energy · SDG 7Mixed
Clean Cooking for Every Home
Three in four people now cook mainly with gas, electricity or other clean options, but about 2 billion still burn wood, charcoal, dung, crop waste, coal or kerosene at home, and in sub-Saharan Africa their number is still rising.
About 2.0 billionPeople cooking mainly with polluting fuels (2024)
Outcome
Moderate
Solutions
High
Reach
Moderate
Housing · SDG 11Worsening
Affordable Homes for All
Nearly half of households worldwide spend more than 30% of their income on housing, house prices have risen faster than incomes since 2010, and the tools known to help, such as social rental housing, housing allowances and zoning reform, reach too few people.
~45%Households worldwide spending over 30% of income on housing (2026)
Outcome
Low
Solutions
Moderate
Reach
Low
Education · SDG 4Mixed
Literacy for Every Adult
About one in eight adults worldwide cannot read and write a simple text, nearly two-thirds of them women, and even in wealthy countries about a quarter of adults read only at the most basic level.
739 millionYouth and adults lacking basic literacy skills (2024)
Outcome
Moderate
Solutions
Moderate
Reach
Low
Education · SDG 4Worsening
Ending Learning Poverty
An estimated seven in ten 10-year-olds in low- and middle-income countries cannot read and understand a short, simple text, even though most of them are enrolled in school.
About 70%10-year-olds in learning poverty in low- and middle-income countries (2022)
Outcome
Low
Solutions
High
Reach
Low
Poverty · SDG 10Stalling
Cheaper Money Transfers Home
Migrants sent an estimated US$729 billion to low- and middle-income countries in 2025, yet sending a typical US$200 still costs more than twice the 3% target, and the poorest corridors and cash users pay the most.
6.36%Average cost of sending US$200 (2025)
Outcome
Moderate
Solutions
High
Reach
Moderate
Poverty · SDG 17Mixed
Debt That Doesn't Crowd Out Development
Borrowing can pay for roads, schools and clinics, but in many developing countries interest bills now take more public money than health or education, and the tools for easing unsustainable debt work slowly and reach few countries.
3.4 billionPeople in countries that spend more on interest than on health or education (2023)
Outcome
Low
Solutions
Moderate
Reach
Low
Health · SDG 3Worsening
Getting the World Moving
Nearly one in three adults and most adolescents do not move enough to protect their health, and the share of inactive adults is rising because streets, schools and daily routines increasingly leave little room for walking, cycling and play.
31%Adults who are not active enough (2022)
Outcome
Low
Solutions
Moderate
Reach
Low
Health · SDG 3Mixed
Controlling High Blood Pressure
High blood pressure is common, usually silent and cheap to treat, yet fewer than one in four of the 1.4 billion adults who have it are diagnosed, treated and brought under control.
1.4 billionAdults aged 30–79 with hypertension (2024)
Outcome
Low
Solutions
High
Reach
Low
Health · SDG 3Mixed
Care for Sickle Cell Disease
Sickle cell disease can be detected at birth and managed with cheap, proven care, yet most of the half a million babies born with it each year are in sub-Saharan Africa, where many children die before age five.
about 515,000Babies born with sickle cell disease (2021)
Outcome
Low
Solutions
High
Reach
Low
Environment · SDG 15Worsening
Protecting Pollinators
Wild bees, butterflies, hoverflies and other animals that pollinate crops and wild plants are declining wherever they are well monitored, driven mainly by habitat loss, intensive farming, pesticides and climate change, while the number of managed honeybee hives has grown worldwide.
10%Wild bee species at risk of extinction in Europe (2025)
Outcome
Low
Solutions
Moderate
Reach
Low

How we describe progress

No problem is “64% solved”. We rate three dimensions separately, plus how reliable the data is and which way things are heading. The ratings are editorial judgements based on the cited sources.

Outcome progress: Has the situation improved in the real world?
Solution maturity: How mature and validated are the available solutions?
Implementation reach: How widely are effective solutions actually used?

The idea boardIdeas from visitors around the world, sorted by colour: solutions, research questions, projects, evidence and local action.See the board

All 100 challenges

Clean Water for Everyone

Alzheimer's Disease and Dementia

Limiting Global Warming

Quality Education for Every Child

Antibiotics That Keep Working

Ending Extreme Poverty

Zero Hunger

Ending Malaria

Every Child Survives Their Fifth Birthday

Clean Air to Breathe

Energy for Everyone

Safe Childbirth for Every Mother

Ending Tuberculosis

Ending AIDS

Mental Health Care for Everyone

Safe Roads for Everyone

Ending Neglected Tropical Diseases

Ready for the Next Pandemic

Safe Toilets for Everyone

Halting Biodiversity Loss

Ending Plastic Pollution

Stopping Deforestation

Saving the World's Wetlands

Wasting Less Food

A Home for Everyone

Ending Child Labour

Ending Violence Against Women and Girls

Safety for People Forced to Flee

Ending Modern Slavery

Internet Access for Everyone

A Family for Every Child

Every Child Vaccinated

Health Care Everyone Can Afford

Surviving Cancer Wherever You Live

Healthy Hearts

Diabetes Care for All

A Tobacco-Free Generation

Living Oceans

Enough Water for People and Nature

Healthy Land and Soil

Safe from Disasters

Every Birth Counted

Childhood, Not Marriage

Decent Work for Young People

A Safe Place for Every Dollar

A World Built for Everyone

Peace and Protection for Civilians

Honest Institutions

Equal Economic Opportunity for Women

Girls Choosing Their Future

No More Preventable Drownings

Ending Viral Hepatitis

Stopping Dengue

Healthy Food Environments

Less Harm from Alcohol

The Last Steps to End Polio

Ending Cholera

No One Dies in Pain

Saving Coral Reefs

Electronics That Don't Poison

Clean Rivers and Lakes

Safe from Extreme Heat

A Decent Home in Every City

Fairer Shares

A Safety Net for Everyone

Thriving Small Farms

Childhoods Free from Violence

Justice for All

Ageing with Dignity

A Qualified Teacher in Every Classroom

A Strong Start for Every Child

Ending Child Stunting

Reducing Anaemia

Stopping Deaths from Sepsis

Closing the Epilepsy Treatment Gap

Preventing Suicide

Preventing Drug Overdose Deaths

Safe Surgery for Everyone

Hearing Care for All