"there are beautiful young people in India"? I think it's a reasonable enough translation
I put "In India there are beautiful young people". Is this syntactically wrong?
Not to me. That's what I put but it was marked incorrect. I'll try suggesting that this answer be accepted.
It is better to say "In India there are beautiful young people.",rather than India has etc.
Why was "In India young people are beautiful" marked incorrect? Should it be होते हैं for that meaning to be conveyed?
I think you are right. With the होते हैं the implication would be that all young people in India are beautiful. Without, it means there are beautiful youngsters, but not necessarily all of them are beautiful.
I put "India has beautiful young people" and was marked wrong. Beautiful == attractive? I think this is a reasonable answer.
It should be "there are beautiful young people in India" not "India has..."
Google translate provides "There are beautiful young people in India." But, if you start with the English (India has beautiful young people.) It produces "भारत में खूबसूरत युवा हैं।" (In India...). I suspect the intent of the duolingo educators is to introduce the nuances around the English verb "to have" when translated into Hindi. If so, they have been less than totally successful, because it's causing more confusion than clarification.
Google translate is not completely reliable in this way. It's good to give you a general idea of what is being said, but still has a lot of quirks.