Reg Validation-Analytical

As per ICH guide line,for linearity and Accuracy we have to cover for 120% of specification level for an impurity during the course of validation. If the same has been fixed as 150%, is it needed to show 120% inbetween. Clarify me.

No. it is not mandatory to include 120% , this is the minimum specified range as given in ICH. You can have any,well distributed concentration levels from your reporting value to 150 % with proper justification.

What should be the recovery limit for impurities (known & unknown) in analytical method validation with respect to specification limit ?

What do you mean the recovery of unknown imopurities? If you don’t know what it is, how do you know the amount? and how do you determine the recovery?