In all places where prisoners are required to live or work:

( a ) The windows shall be large enough to enable the prisoners to read or work by natural light, and shall be so constructed that they can allow the entrance of fresh air whether or not there is artificial ventilation;

( b ) Artificial light shall be provided sufficient for the prisoners to read or work without injury to eyesight.

1. The physician or competent public health body shall regularly inspect and advise the prison director on:
[...]
(c) The sanitation, temperature, lighting and ventilation of the prison [...]

General living conditions addressed in these rules, including those related to light, ventilation, temperature, sanitation, nutrition, drinking water, access to open air and physical exercise, personal hygiene, health care and adequate personal space, shall apply to all prisoners without exception.

In all buildings where prisoners are required to live, work or congregate:

a. the windows shall be large enough to enable the prisoners to read or work by natural light in normal conditions and shall allow the entrance of fresh air except where there is an adequate air conditioning system;

b. artificial light shall satisfy recognised technical standards;

Persons deprived of liberty shall have adequate floor space, daily exposure to natural light, appropriate ventilation and heating, according to the climatic conditions of their place of deprivation of liberty. (…)The installations shall take into account the special needs of the sick, persons with disabilities, children, pregnant women or breastfeeding mothers, and the elderly, amongst others.

The CPT frequently encounters devices, such as metal shutters, slats, or plates fitted to cell windows, which deprive prisoners of access to natural light and prevent fresh air fromentering the accommodation. They are a particularly common feature of establishments holding pre-trial prisoners. The CPT fully accepts that specific security measures designed to prevent the risk of collusion and/or criminal activities may well be required in respect of certain prisoners. However, the imposition of measures of this kind should be the exception rather than the rule. This implies that the relevant authorities must examine the case of each prisoner in order to ascertain whether specific security measures are really justified in his/her case. Further, even when such measures are required, they should never involve depriving the prisoners concerned of natural light and fresh air. The latter are basic elements of life which every prisoner is entitled to enjoy; moreover, the absence of these elements generates conditions favourable to the spread of diseases and in particular tuberculosis.

The CPT recognises that the delivery of decent living conditions in penitentiary establishments can be very costly and improvements are hampered in many countries by lack of funds. However, removing devices blocking the windows of prisoner accommodation (and fitting, in those exceptional cases where this is necessary, alternative security devices of an appropriate design) should not involve considerable investment and, at the same time, would be of great benefit for all concerned.

A well-designed juvenile detention centre will provide positive and personalised conditions of detention for young persons deprived of their liberty. In addition to being of an adequate size, well lit and ventilated, juveniles' sleeping and living areas should be properly furnished, well-decorated and offer appropriate visual stimuli. Unless there are compelling security reasons to the contrary, juveniles should be allowed to keep a reasonable quantity of personal items.

The cells used for solitary confinement should meet the same minimum standards as those applicable to other prisoner accommodation. Thus, they should be of an adequate size, enjoy access to natural light and be equipped with artificial lighting (in both cases sufficient to read by), and have adequate heating and ventilation. They should also be equipped with a means of communication with prison staff. Proper arrangements should be made for the prisoners to meet the needs of nature in a decent fashion at all times and to shower at least as often as prisoners in normal regime. Prisoners held in solitary confinement should be allowed to wear normal prison clothing and the food provided to them should be the normal prison diet, including special diets when required. As for the exercise area used by such prisoners, it should be sufficiently large to enable them genuinely to exert themselves and should have some means of protection from the elements.

All too often, CPT delegations find that one or more of these basic requirements are not met, in particular in respect of prisoners undergoing solitary confinement as a disciplinary sanction. For example, the cells designed for this type of solitary confinement are sometimes located in basement areas, with inadequate access to natural light and ventilation and prone to dampness. And it is not unusual for the cells to be too small, sometimes measuring as little as 3 to 4 m2; in this connection, the CPT wishes to stress that any cell measuring less than 6 m2 should be withdrawn from service as prisoner accommodation. The exercise areas used by the prisoners concerned are also frequently inadequate.