This is what happens to urban areas when there is a grand plan -- something that might involve demolishing existing buildings -- under discussion but not decided upon (perhaps there's a dispute over planning permission or there are problems finding the money). The motivation to maintain the existing buildings and streetscape is lost. What's the point, when it's all going to be pulled down soon? Things gradually decay. You can see it at the moment in Cambridge in the area around the railway station.
Recently I've realised that planning blight can happen on a domestic scale too, and that in fact our own house and garden have got a bad case of it. Ever since we moved into this house (2001) we've known that we wanted to make radical changes. (We bought it because of its location.) This culminated last year in a scheme to demolish the whole thing and start again. I was quite enamoured of the idea for several months and am only gradually being persuaded out of it by my more cautious other half.
Meanwhile none of the over-counter lighting in the kitchen works any more.