More information on Tier 1 mitigations is located here
Tier 1 mitigations may be applied to regions that are experiencing a sustained resurgence of COVID-19 or regions that have been under more stringent mitigations but have not yet achieved metrics that allow for a resumption of Phase 4 Restore Illinois activities. If a region again experiences a sustained resurgence of COVID-19 with Tier 1 mitigations in place, a return to stricter measures may be necessary to curtail further spread.