Some things are not to be there to proven. If there is a myth or a story behind this, then some reason is behind in this.
Bhangarh will be known as the top most haunted places in the world, no personal experience though, just heard stuff like that, because i like to read and wanted to know horror, thats why when i visited jaipur last time so i asked about the place. They don't know about what's the right story behind this but they do fear to go in night.
i dont have any evidence whats in there but i do believe that something is there otherwise it wont be so popular as haunted place.