36 Efforts aimed at improving capacities for accommodation of detainees are encouraging. During 2013, ​​numerous adaptations and reconstructions of accommodation capacities were carried out. During 2013, works on reconstruction of one part of the detention unit of District Prison in Belgrade were carried out, in compliance with applicable regulations and standards. After conducted visits and sent recommendations by the NPM, a reconstruction of one part of the detention unit of the Juvenile Penal Correctional Facility in Valjevo107, as well as the reconstruction of detention units of the District Prison in Negotin108 were carried out, in which way the material conditions of accommodation met the pertinent standards. However, despite the recommendations109 made, detention units of some institutions for execution of criminal sanctions, material conditions of accommodation still fail to comply with applicable standards. The problem of the system of the execution of detention measures in Serbia, is that detainees are closed all day, i.e. locked in a cell / dormitory. As a general rule, detainees are not permitted to spend their free time during the day outside the cell, in the common areas with other detainees with whom they are not prohibited to contact on the basis of a court decision. In most cases, they are not allowed to work, nor involved in social and cultural activities. Notwithstanding according to the existing regulations detainees have the right to spending at least 2 hours outdoors every day, some detention units do not provide conditions for the realization of this right to the full extent. Existing walking areas generally do not have adequate eaves, suitable for protection from precipitation. Moreover, facilities intended for physical activity are inadequate, especially under adverse weather conditions. Not enough attention is paid to the placement of detainees in the detention premises. It was noted that detainees who have not been previously convicted are placed in the same dormitory with detainees with prior convictions, and at the same time not enough attention is paid to the placement of detainees depending on the type of criminal offence they are accused of110. The abovementioned is not in accordance with the existing standards and can have far-reaching negative consequences for the detainees. A particular problem represents the placement of juvenile detainees in the same room with adult ones. Due to the current system of enforcement of detention measures, it often happens that the female detainees spend detention measures mainly in isolation. because of their relatively small number Women on whom the detention measure have been imposed, are placed in detention units in prisons throughout Serbia. Due to their relatively small number in one detention unit, it often happens that some of them spend detention measures practically in isolation, for inappropriately long period of time. Although in the system of execution of criminal sanctions it represents a disciplinary or special measure which is strictly limited, in the current practice, for certain detainees it is a regular manner of execution of the detention measure, which speaks volumes about the existing negative aspect regarding the detention of women. 107 Recommendation No. 12-1949/13 from 11 July 2013. 108 NPM report on the visit to District Prison in Negotin, No. 71-98/12. 109 NPM report on the visit to District Prison in Kraljevo, No. 71-164/12; NPM report on the visit to District Prison in Kragujevac, No. 71-3/13, NPM report on the visit to District Prison in Pančevo, No. 71-28/13. 110 NPM report on the visit to District Prison in Kragujevac, No. 71-3/13; NPM report on the follow-up visit to Penal Correctional Institution in Sremska Mitrovica, No. 71-48/13.