It could be any number of reasons:
Maybe when it was originally sold it was in good condition, and now it has had the kitchen and bathroom ripped out.
Maybe it is because the property is in an area where there have been recent local issues such as riots and high crime.
Maybe there has been a flood and the whole bottom of the house is riddled with damp.
There are about a hundred reasons this could have happened - without further information there is no way to tell.