(b) Property so acquired by an agency, or by a municipality in behalf of an agency, shall be exempt from taxation until sold, leased for a term not exceeding ninety-nine years or otherwise disposed of in accordance with the provisions of this article or article fifteen of this chapter; provided, however, that any such agency shall have the power and authority, with respect to such property, to pay, out of funds available to it for the effectuating of such urban renewal program, annual sums in lieu of taxes to any taxing jurisdiction providing services to the urban renewal area, or to the part or portion thereof within such taxing jurisdiction, in order that no such taxing jurisdiction shall suffer an inequitable loss of revenue by virtue of such urban renewal program; provided, further, that the amount so paid for any year with respect to any such property shall not exceed the lesser of (1) the sum last levied for the benefit of such taxing jurisdiction as an annual tax on such property prior to the time of its acquisition for urban renewal purposes or (2) such amount as shall be approved by the commissioner, pursuant to such rules, regulation, limitations and conditions as he may prescribe, as an eligible and proper charge against such urban renewal program. Upon the sale, lease or disposition of such property to any person, firm or corporation not entitled to an exemption from taxation or entitled to only a partial tax exemption such property shall immediately become subject to taxation in whole or in part, as the case may be, and shall be taxed pro rata for the unexpired portion of the taxable year. As used in this paragraph, the term "taxing jurisdiction" means any municipal corporation or district corporation including any school district or any special district, having the power to levy or collect taxes and benefit assessments upon real property, or in whose behalf such taxes or benefit assessments may be levied or collected.