It's a yoga pose. It is said to burn up toxins in the body. It is also said to burn up bad karma.
Now, the first of those claims is just wrong, but at least in theory, you could try and prove it.
The second one however.... now that is just funny. How do people come up with shit like that? Even assuming you're a believer, how would one go about finding out whether this is true?
It also completely contradicts the often-claimed truism that "karma is just cause and effect". If that is the case, then how would a pose change any of that?