As state and national pressures build to reduce diesel pollution at sea ports, the Port of San Diego has started exploring ways to slash emissions from cruise liners and other ships that call on the city. No one tracks how much air pollution the Port of San Diego creates, but it's widely agreed that having massive diesel engines from cruise liners and other ships idling for hours at the pier isn't good for air quality. The effort centers on providing dockside power so vessels can plug in and turn off their diesel engines, a process called cold ironing. A growing...