The World Health Organisation (WHO) has warned of the growing risk of heat-related illnesses at mass gatherings and issued new prevention and management guidelines to help event organisers and host countries plan and deliver safer events.
According to a WHO statement, heat-related illnesses at mass gatherings, including major sporting, religious and cultural events, have become a significant threat to public health and operational continuity. The risks affect spectators, attendees, volunteers and staff, potentially placing additional pressure on medical services and emergency response systems.
The organisation’s review of evidence from studies published between 1980 and 2025 drew on data documenting nearly 500,000 cases requiring medical care at mass gatherings, including more than 22,000 heat-related illnesses. The findings highlighted the importance of well-organised on-site medical systems, which can treat more than 90% of patients at event venues, substantially reducing pressure on local hospitals and ambulance services.
Dr Chikwe Ihekweazu, Executive Director of the WHO Health Emergencies Programme, said extreme heat posed a growing threat to health, safety and operational continuity at mass gatherings. He stressed that heat should be addressed not merely as an environmental hazard, but also as a major operational and governance challenge. WHO estimates indicate that heat-related deaths have increased by 63% since the 1990s, with an average of 546,000 deaths recorded annually between 2012 and 2021.
The WHO noted that mass gatherings can amplify heat-related risks through a combination of prolonged outdoor exposure, high temperatures and direct sunlight, crowded conditions, limited access to safe drinking water, travel-related fatigue, unfamiliarity with local climatic conditions and competing demands on healthcare services.
The Intergovernmental Panel on Climate Change (IPCC) has reported that extreme heat events, including heatwaves, have become more frequent and intense across most land regions since the 1950s, primarily due to climate change. The frequency and intensity of these events are expected to increase further with every additional rise in global warming.
To help host countries and event organisers anticipate and better manage heat-related health risks, the WHO has released a new set of resources entitled Prevention and Management of Heat-Related Illness at Mass Gatherings. The guidance draws on evidence compiled through systematic reviews of research, as well as lessons learned from mass gatherings held around the world.
The organisation highlighted several essential preparedness and prevention measures that should be implemented before temperatures reach dangerous levels. These include ensuring an adequate supply of safe drinking water that is readily accessible to attendees, providing sufficient healthcare facilities and cooling infrastructure, adjusting event schedules, improving crowd management and movement, protecting workers, strengthening public communication and real-time monitoring, and ensuring that well-prepared medical services are available on site.
