Why does pollution often remain near its discharge source in the Mediterranean Sea?

In the Mediterranean Sea, pollution tends to remain near its point of discharge primarily because of relatively weak tidal and current movements in the region.1

While industrialization, tourism, and growing coastal populations have led to significant water pollution in many areas, the lack of strong water circulation prevents the rapid dispersal of these pollutants. To address this environmental challenge, countries in the region have collaborated on the Mediterranean Action Plan (Med Plan), which includes legal frameworks like the Barcelona Convention and the Athens Protocol to monitor and control land-based pollution sources. Despite these efforts, improvements in overall environmental quality have remained limited.1