Kaala Pani is how the British called the islands. Very briefly, the British brought in convicts from all over India and Burma and created a settlement on the islands. They also set up the cellular jail. They gave land to people to clear it of forests and settle there. For a long time there was hostility with the Jawaras, the tribals. At the moment it is peace! Today Andaman is like a mini India.
So basically there are 3 sections of the islands, the tribals (beyond our reach), the locals you meet everywhere and the 3 rd, the buffer zone where the tribals and locals interact! The Jawaras mingle with locals for food. The locals visit the jungles for wood and honey. (So hey say!) But the sentinels stay in their own world, separate. I found the stories of mingling most fascinating!
Here is an interesting book I found in a shop at Havelock and it gave a lot of information. The author used real life incidents to weave them into a story.