I believe that more people are hosting more backyard bonfires in Chicago in order to spend time with friends outdoors, because it’s one of the lowest risk ways to still enjoy life during the COVID-19 pandemic that Trump is prolonging.
The City of Chicago has rules on what can be burned. Be sensitive to neighbors who rely in keeping their windows open to cool and ventilate their homes.
The summary version is this: You can burn manufactured firewood that you purchased, and you can burn wood logs from any trees someone manually cut. All logs have to be untreated and two feet long or shorter.
You can’t burn scrap wood, lumber, plywood, or particle board. You also cannot burn garbage. Avoid having bonfires when the wind speed is 15 miles per hour or faster.
Read all the rules in this PDF. The rules aren’t in the municipal code; the code in section 11-4-740 says that the environment commissioner shall make rules (Chicago doesn’t currently have a department of environment).