Europe’s heatwaves expose overcrowded, aging prisons as health risk

Temperatures climbed past 37 degrees Celsius in Orléans, France, as Europe’s heatwaves pushed overcrowded prisons into conditions that prison watchdogs have long warned can threaten health and basic dignity. Reuters said the pressure was most acute in France, Italy and Belgium, where jail occupancy levels ran at roughly 120% to 140%.

Severe overcrowding also was reported in six countries in a Reuters social post: Slovenia, Cyprus, France, Italy, Romania and Belgium. In France, a separate Reuters-linked summary said the prison occupancy rate stood at 141.3% on July 1, while the prison population exceeded 85,370 inmates as of Nov. 1, 2025. France 24 reported on June 25 that some French prisons were holding three or four detainees in cells built for one.

The heat is colliding with an older problem: many European prisons were built decades ago, and some date back centuries. In cramped cells with poor ventilation and little or no cooling, high temperatures can linger long after dusk. That raises the risk of dehydration, exhaustion, violence and sanitation failures for both inmates and staff, turning a summer spike into a public-health problem inside closed institutions.

The UN Subcommittee on Prevention of Torture visited France from May 17 to May 23, 2026, and urged urgent structural measures to address severe overcrowding, warning that conditions in some facilities may violate the fundamental rights of people deprived of liberty. The Council of Europe’s white paper on prison overcrowding said the European Court of Human Rights recommends replacing old and worn-out prison buildings with new modern prisons offering humane conditions of detention.

Reuters’ reporting, published Aug. 7 and linked to the bylines of Layli Foroudi, Alvise Armellini and Amina Ismail, showed how quickly extreme heat turns a chronic capacity crisis into an emergency. The same pattern had already appeared in January 2023, when Reuters posted that twelve prison administrations in countries with more than 500,000 inhabitants reported overcrowding.

French prisons have become a recurring pressure point. A France 24 report in June described detainees being crammed into hot cells, and the country’s anti-torture and prison watchdog bodies have repeatedly criticized worsening detention conditions. Reuters-linked summaries also said Italy faced pressure to release up to 10,000 people from prison in 2025 to ease overcrowding, a sign that governments have known the scale of the problem even as reforms have lagged behind the climate.