New York and Boston have also experimented with dry ice as a rodent control technique. (Dry ice: Shawn Henning / Rat: National Park Service)

Mayor Rahm Emanuel and the Department of Streets and Sanitation on Tuesday announced a pilot program that uses dry ice to curb rodent infestations.

Photo by Patty Wolf

Some city officials, landlords and service providers say they are seeing an uptick in reported cases of hoarding in the Chicago area. We unpack what's behind this perceived increase, and the challenges of addressing what in some cases could be considered a mental illness.