NEWS Incident: United B737 at Chicago on Feb 3rd 2015, cabin did not pressurize

A United Boeing 737-900, registration N67815 performing flight UA-1218 from Chicago,IL to Denver,CO (USA) with 175 passengers, was climbing through 15000 feet out of Chicago when the crew stopped the climb and descended to 10,000 feet due to the cabin not properly pressurizing.