What kind of spider is this?(Rajasthan, India)
That's neither a spider nor a scorpion (and, of course, not an insect). That's a solifuge, a different group of Arachnida. 

The most common Genus of solifugae in India is Galeodes, which resembles the specimen in your photo:



Genus Galeodes

However, narrowing it down to the Genus may be a little bit more complicated.

It's worth mentioning that, despite their frightening appearance, they are not dangerous to humans.