Tyler LaRiviere/Sun-Times, Tyler LaRiviere/Sun-Times Mayor Lori Lightfoot’s administration is seeking more information about the cumulative air pollution around a proposed scrap-metal shredding operation on the Southeast Side, an inquiry that delays the city’s permitting for the controversial business. The city has been reviewing an operating permit application from Reserve Management Group, which acquired Lincoln Park-based General Iron in 2019. The company has been building a new facility at East 116th Street along the Calumet River to relocate General Iron, as the rebranded Southside Recycling, next to RMG’s existing businesses. In a letter Monday, a city environmental official told RMG that it requires more information “to properly assess the relationship between and the potential cumulative impact of all Reserve Management Group operations” in the area. Air pollution throughout the Southeast Side is among the worst in the city.