Is there a facial feature particularly unique to people from India ?
Most People of Indian origin, particularly with "traditional indian looks", have an enlarged upper "eyelid fold" above eye lashes. The fold is prominent even with their eyes fully open.
This fold is not prominent in people from other continents and people from Northern / Eastern Asia.
Attached is the picture of an Indian Actor known for her traditional Indian looks, the fold is prominent above her eye lashes. Indian actors with western looks do not have it. Conversely, some actors in western world known for unconventional looks have this prominent fold. It may be interesting to note that while Sylvestor Stallone has this facial feature, Morgan freeman does not.
With the recent news about Prince William, it is interesting to note that some pictures of Prince William do show this facial feature, example: (http://www.eonline.com/news/394242/father-to-be-prince-william-speaks-out-against-poaching-watch-now)