Sustainability is the new imperative for urban leaders. And now there is a new way to encourage and even measure a community's sustainability. It's called Leadership in Energy and Environmental Design for Neighborhood Development -- LEED-ND for short - and it extends criteria for green building to neighborhoods. Jennifer Henry from the U.S. Green Building Council is with us to talk about the new guidelines and the impact they will have on cities.

Also with us is Dr. Helen Mulligan who has been exploring ways that cities, particularly older industrial cities, can take advantage of the growing interest in green technologies to fuel local economic development. Helen is a director of Cambridge Architectural Research Limited.

Our subject is the greening of cities, this week on Smart City.