CAT/C/BHR/CO/2-3 inhuman or degrading punishment or, depending on the circumstances, torture (arts. 2, 1113 and 16). 21. The State party should: (a) Effectively implement current national legislation in order to ensure that solitary confinement remains an exceptional measure, imposed for as short a time as possible and is used as a measure of last resort, in accordance with international standards; (b) Ensure that solitary confinement is kept under strict supervision and judicial review, that it never lasts longer than provided for by law and that the detainees are guaranteed due process rights, such as the right to appeal; (c) Establish clear and specific criteria for decisions on isolation and ensure that the practice of renewing and prolonging solitary confinement is strictly prohibited; (d) Ensure that the detainee’s physical and mental condition is monitored daily by qualified medical personnel throughout the period of solitary confinement, in accordance with the United Nations Standard Minimum Rules for the Treatment of Prisoners (the Nelson Mandela Rules); (e) Put an end to the solitary confinement of Nabeel Rajab and ensure that he is provided with adequate medical assistance and redress. Conditions of detention 22. While taking note of information about the construction of new buildings to accommodate inmates, the Committee is concerned that overcrowding remains a problem in detention facilities. It is also concerned at reports of poor material and hygiene conditions in places of detention, including inadequate bathing and toilet facilities, lack of access to adequate quantities of food and to good quality food, lack of access to health care, lack of outdoor activities and unnecessary restrictions on family visits (arts. 2, 11-14 and 16). 23. The State party should: (a) Intensify its efforts to bring the conditions of detention in places of deprivation of liberty into line with the Nelson Mandela Rules and the United Nations Rules for the Treatment of Women Prisoners and Non-custodial Measures for Women Offenders (the Bangkok Rules); (b) Further reduce prison overcrowding in all places of detention, including by building additional facilities, renovating existing ones and reducing the rate of incarceration; (c) Ensure that detainees are provided with adequate material and hygiene conditions, including bathing and toilet facilities, adequate quantities of good quality food, space per prisoner, health care, outdoor activities and family visits; (d) Allow independent monitoring bodies, including international bodies, to carry out regular unannounced visits to all places of detention and to meet in private with detained persons. Riots in prisons 24. The Committee is concerned at reports of outbreaks of violence by inmates in prisons resulting in riots and inmates escaping, as was the case in Jaw Prison in March 2015 and January 2017 and in Dry Dock Prison in 2016. The reports make reference to the excessive use of force by security forces in Jaw Prison, including their use of rubber bullets, tear gas and shotguns, as well as the harsh treatment of the detainees by the prison administration, which included forcing inmates to spend 10 days in the open courtyard and the transfer of 100 detainees to another section of the prison where they were reportedly subjected to collective punishment amounting to ill-treatment and torture. It has been 6