Run airtel xtreme box without dish installation.

No.

I too have personally looked on internet, reddit, forums for the same. 

because airtel is now providing free airtel box, but found no solution.

only way I found is get a black plan with your airtel fiber and pay just extra Rs 118 for dth.

If the box runs on android 10 ( old box) , i saw a few youtube hacks to run apps ( search on youtube) and if its running android 11 ( new box that i have currently. There is a newer version, i heard,  came 4-5 months back). i think that youtube trick was not working. I dont remember, but read some blogs where they loaded custom android os, but some reported it making brick.

Search and do it with own risk