35 ILCS 200/21-397
In counties with 3,000,000 or more inhabitants, if an order is entered setting aside a redemption made within the time allowed by law after a petition for tax deed has been filed, the holder of the certificate of purchase shall mail a copy of the order within 7 days of entry of the order by registered or certified mail to the county clerk, to the person who made the redemption, and to all parties entitled to notice of the petition under Section 22-10, 22-15, or 22-25. The order shall provide that any person who was entitled to redeem may pay to the county clerk within 30 days after the entry of the order the amount necessary to redeem the property from the sale as of the last day of the period of redemption. The county clerk shall make an entry in the annual tax judgment, sale, redemption, and forfeiture record reflecting the entry of the order and shall immediately upon request provide an estimate of the amount required to effect a redemption as of the last date of the period of redemption. If the amount is paid within 30 days after entry of the order, then the court shall enter an order declaring the taxes to be paid as if the property had been redeemed within the time required by law and dismissing the petition for tax deed. A tax deed shall not be issued within the 30-day period. Upon surrender of the certificate of purchase, the county clerk shall distribute the funds deposited as if a timely redemption had been made. This Section applies to all redemptions that occur after the effective date of this amendatory Act of the 91st General Assembly.
35 ILCS 200/21-397