Mongol Invasion of India

What would it take to get the Mongols to invade India and hold it? I've got a timeline in my head where a strong Persian Empire is still standing, which would stop the Mongols from getting deep into the Middle East and result in them moving against India instead. Is that the kind of thing it would take to make the Mongols mount an invasion of India, or is there some POD after Genghis emerges that would result in the same thing?
 
I thought that the Mongols realy did invade India....

I was thinking of something along the lines of it being a primary objective for one of the earlier Khans (e.g. through Kublai), and possibly an additional Khanate like the Ilkhans and Golden Horde. As far as I know no such kingdom was established.
 
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