With the advent of globalisation we are no longer used to the seasonality of foods. If you want asparagus out of season it can be flown in from half-way around the world to the shelves of the local Tesco supermarket.
Sourcing from local suppliers is a way of reducing the carbon footprint of your shopping basket. There is an attraction for retailers targeting the socially conscious consumer to play up the local nature of a product, where these claims are optimistic or outright lies is localwashing.
Kudos to Piers Fawkes over at PSFK for this definition.