"My grandparents live in India."

Translation: मेरे दादा-दादी भारत में रहते हैं।

[arebhai]

Is there no single word for grandparents?

[vinay92]

No. There is also no single word for parents. It is usually माता-पिता or मां-बाप.

[egcw1995]

Why is नाना-नानी not correct here?

[dinekum]

Those are parents of mother...
But दादा-दादी are parents of father...
So there is clear differentiation in relationships...
While in other languages this matter omitted so always cofusion...

[vinay92]

It is correct. You can report it if you see the sentence again.

[Rodrigo188394]

Is the word or possible also in this sentence ?

[srivassumit]

If you meant मेरे दादा और दादी then yes that would be correct too but the hyphenated दादा-दादी is more common to use.