This is showing many false positives from the index scan that get removed when the actual values are examined. With such a long search parameter, that does not seem surprising. I would expect a search on "raj nagar ghaziabad 201017" or something like that to yield far fewer results from the index scan. I don't know GIN indexes super well, but I would guess that including words that are very common will yield false positives that get filtered out later.
