Prison overcrowding is one of the key contributing factors to poor prison conditions around the world. It is arguably the biggest single problem facing prison systems; its consequences can be life-threatening at worst and at best prevent prisons from fulfilling their proper function. Prisons in over 124 countries exceed their maximum occupancy rate, with 23 national prison systems at more than double their capacity. In 2020, many prison systems announced unprecedented mass releases of people in prison to reduce overcrowding and the risk of the transmission of COVID-19 in places of detention.
The overuse of solitary confinement in prisons around the world is becoming an increasing concern. Some form of short-term isolation from the rest of the prison population is used almost everywhere as punishment for breaches of prison discipline. However, many states increasingly use solitary confinement routinely and for longer periods of time. There are major concerns for the physical and mental health of persons subjected to the practice.
States have an obligation to protect the lives and well-being of people in custody. States also have an obligation – in line with the prohibition on ill-treatment and the right to health – to ensure hygiene and adequate healthcare in prisons. Poor sanitary conditions, inadequate lighting and ventilation, extremes of temperature, insect and rodent infestation and insufficient or non-existent personal hygiene supplies all have a negative impact on the health of persons detained.
Rates of infectious disease, notably HIV/AIDS and TB, are much higher in prisons than in the rest of the population in most countries.