Very simple

In pure form that is in its intrinsic nature the semi conductors are having no electrons in free state

And so the fermi level is in the middle of the Ed and Ea layer But in the Extrinsic semi conductors there is a shift in the curve. From a straight line to a curve

But when the curve touches the Ed or Ea line there is a balance in the number of conducting electrons and holes in the atom

how is the balance in number of conducting electrons and holes justified? Not understood the physical interpretation of this touching of Ef with Ed or Ev