According to the article, Hamas prison cells meant for 20 people routinely have as many as 80.
In the summer, temperatures can go past 40 degrees C (104F) with no ventilation.
Prisoners with deadly contagious diseases are herded next to others. There are no doctors available, ever.
Prisons are also filled with bugs because of how filthy they are.
And, of course, some prisoners are tortured and killed. The Independent Commission for Human Rights documented 21 cases of Hamas prisoners who died last year, most of them executed. They also received 996 complaints about torture in 2014.
Too bad Gaza doesn't have any internationally funded "pro-Palestinian" NGOs around who are interested in documenting these issues and publicizing them. It would be nice if Amnesty, HRW and Oxfam showed interest in the issue of prison conditions in Gaza. (HRW did once issue a report on Hamas torture, in 2012.)