65 ILCS 5/9-2-82
In counties having a population of 1,000,000 or more the collector shall, on or before the first day of August in each year, make a report in writing to the general officer of the county (in which the respective lots, tracts, and parcels of land are situated) authorized by the general revenue laws of this State to apply for judgment and sell land for taxes due the county and State, of all the land, town lots, and real property on which he has been unable to collect special assessments or special taxes, or installments thereof matured and payable, or interest thereon, or interest due to the preceding January 2 on installments not yet matured on all warrants in his possession, with the amount of those delinquent special assessments or special taxes or installments and interest together with his warrants; or, in case of an assessment levied to be paid by installments, with a brief description of the nature of the warrant or warrants received by him authorizing the collection thereof. This report shall be accompanied with the oath of the collector (1) that the list is a correct return and report of the land, town lots, and real property on which the special assessment or special tax (levied by the authority of the city or incorporated town or village of .... as the case may be), or installments thereof, or interest, remains due and unpaid, (2) that he is unable to collect the same, or any part thereof, and (3) that he has given the notice required by law that the specified warrants have been received by him for collection.
65 ILCS 5/9-2-82