The Borrower shall, and shall cause each Significant Subsidiary to, pay and discharge promptly when due all taxes, assessments and governmental charges or levies imposed upon it or upon its income or profits or in respect of its property, before the same shall become delinquent or in default, as well as all lawful claims for labor, materials and supplies or otherwise which, if unpaid, might give rise to a Lien upon such properties or any part thereof; provided , however , that such payment and discharge shall not be required with respect to any such tax, assessment, charge, levy or claim so long as the validity or amount thereof shall be contested in good faith by appropriate proceedings and the Borrower shall, to the extent required by GAAP, have set aside on its books adequate reserves with respect thereto.