Azerbaijani company ADOG and Zira International Port propose to connect Caspian and Black seas via a tunne3l of diameter 10 meters. This will transfer water from Black sea to Caspian sea. In recent years, Caspian sea water levels are falling. Such a tunnel would go under Russia and Georgia.have proposed building an underground tunnel that will connect the Caspian and Black Seas, minval.az reports.

https://kz.kursiv.media/2025-05-02/zhki-v-azerbajdzhane-predlozhili-soedinit-kaspij-i-chernoe-more/