This week's cover story asks why Chicago resists legalizing eloteros. It's a long battle - in 1997, Neal Pollack investigated the same question:
"Street vending has been intermittently under attack in Chicago for decades, but the latest crackdown began in 1991, when aldermen started to pass peddling "moratoriums" in various wards. Bernard Stone was the first, banning street vendors in the 50th Ward. His idea quickly caught on, and soon the streets were being cleared on the northwest and southwest sides. Then the moratoriums started popping up on the south side, as well as in more gentrified north-side areas like Lakeview and Lincoln Park. Alderman Burton Natarus, whose 42nd Ward now includes most of downtown, sponsored a law that forbids street vending anywhere in the Loop (with the exception of city-commissioned fruit stands on State Street). The Park District added its own citywide ban last summer. In the few remaining wards that still allowed food peddling, vendors were pretty much left alone. Last month the boom came down."
H/t @WBEZ for the reminder. Chicago's not alone, of course; Ed Koch threw down against street vendors in New York in the '80s. Streetvendor.org is a good roundup of the legal issues pushcart sellers face.