In fact condition of a shelter usually depends on its type and purpose. Thus, shelters for officials are almost always in an excellent condition, the same is about the shelters under state institutions, worse are those under acting science objects and even more worse - under large hospitals.
Shelters under factories are usually in the same condition as the factories themselves. However district shelters either look terrible or adopted for other purposes. But what about the crowded places? Let's look at the example of one international airport in Moscow.