There is a lot more slavery in Nouakchott because that is where the Arab-Berber ruling class, which needs slaves, lives. There are no regions in particular, but there is slavery where the Arab-Berber populations live. In fact, their way of life and culture are based on slavery. In their communities, they cannot live day to day without slaves. Slavery is part of their code of honour and way of life.
On June 12th, 2017. See this statement in context.