Katherine Gajewski was just 29 years old when Philadelphia Mayor Michael Nutter asked her to take on the role of city sustainability director. “I was concerned that people wouldn’t take me seriously,” she says. Three years later, those fears have all but disappeared. Using limited staff and resources, her office works long days to earn Philly a green reputation. “Once people see that you’re really serious and you’re working really hard, age isn’t a factor,” she says. Gajewski works to implement the ambitious city-wide Greenworks Philadelphia plan [PDF], directs a five-county energy-efficiency program, and even organizes a social group of city employees nicknamed the “Young-ish City Government Workers.” For episode 2 of our series about women who are leading the charge to make our cities more sustainable, Gajewski tells Grist about Philly’s lovely bones and her vision for the future (while also making everyone here feel a bit unaccomplished-ish).