The Borrower shall pay and discharge when due, and cause each of the Subsidiaries so to do, all Taxes imposed upon it or upon its property, which if unpaid would, individually or collectively, reasonably be expected to have a Material Adverse Effect or become a Lien on the property of the Borrower or such Subsidiary (other than a Lien described in clause (a) of the definition of Permitted Encumbrances), as the case may be, unless and to the extent only that such Taxes shall be contested in good faith and by appropriate proceedings diligently conducted by the Borrower or such Subsidiary, as the case may be.