In my textbook it said that helium is used in oxygen tanks (diving apparatus) by deep sea divers.
When I searched the internet for the reason it said that :
A mix of helium and oxygen is used in diving apparatus by deep sea divers, due to low solubility of helium in blood even at high pressure.
Why to mix helium when we can just fill the tanks with pure oxygen?
Why can't other inert gas be used in place of helium?