Healthier environments could prevent almost one quarter of the global burden of disease. The COVID-19 pandemic is a further reminder of the delicate relationship between people and our planet. Clean air, stable climate, adequate water, sanitation and hygiene, safe use of chemicals, protection from radiation, healthy and safe workplaces, sound agricultural practices, health-supportive cities and built environments, and a preserved nature are all prerequisites for good health. Disease agents and exposure pathways are numerous and unhealthy environmental conditions are common, with the result that most disease and injury categories are being impacted. Noncommunicable diseases, including ischaemic heart disease, chronic respiratory diseases and cancers are the most frequent disease outcomes caused. Injuries, respiratory infections and stroke follow closely.