If one were to take a cursory look at the history of these people as they wrote it down, they categorically state as a matter of fact that they are the inheritors of a civilization stretching back to 9,000 - 10,000 BCE. There were 3 "Sangams" or "civilization phases" that had to be relocated every 4,000 years or so due to rising oceans (or sinking land.) It has been dismissed as a legend or myth in spite of little to no marine archaeology undertaken in the area, in spite of bathymetric studies done by Prof. Glen Milne (quoted in Graham's "Underworld" with data and sea level simulation maps) that show the majority of the Sunda Shelf (the area between India and Indonesia) as being above sea level during the ice age, and gradually submerging between 9,000 BCE and present day in phases as sea levels rose.
Those dates and figures make a lot more sense. Now we're well within the post-glacial sea rise. Turns out the 'myth' paints a more accurate picture than our 'scientific' (read: based on 19th century religious beliefs) notions. Who woulda thunk it? :)
It's a very interesting area because it has landmasses that were only submerged after the end of the last ice age. And it were regions more suitable to support large groups of people thus centers of civilization. We have Doggerland over here. It would certainly be fun to see a dolmen discovered at a land that got submerged 8,000 years ago. But I don't expect there to be large settlements, let alone anything what could be called cities. The seas from the Persian Gulf all the way to Sunda Shelf, or even Japan, is the place to look. Sad humanity is operating at such a primitive level we have all the money in the world to spend on bombs and next to nothing for trying to rediscover our lost history.