Sadly, they don't think there are enough islanders to keep up a stable population.
India seems determined to keep it off limits; the fishermen who dropped the last guy off got a lot of jail time and I expect Indian prison isn't very nice.

@Beowulfsfriend Yeah, you need to start with about 500 persons in order to maintain enough genetic diversity and hopefully avoid inbreeding and associated problems.

@snytiger6 They have been secluded on this island with little outside DNA for many generation. Because of their seclusion there is not much that can be done to see the effects of this isolation. And worry about diversity is a fairly new issue. Centuries ago it was quite common.

@Barnie2years Yes, by limiting the gene pools, and trying to keep blood lines pure, most of the royal families of centuries past had to deal with inherited diseases, which were recessive until the gene pools were so limited.