The provisions of this act are applicable only in cases where all the bond, interest and judgment indebtedness of such municipal subdivision for which such sinking fund levies for such previous years were made and which is or was an obligation of such sinking fund has either been paid, or is subject to immediate payment out of unencumbered and unappropriated cash then in said sinking fund, or refunded or reduced to judgment and legal provision made for payment thereof out of sinking fund levies, or otherwise, within the current and/or future fiscal years.