Hindi Poster Underneath a Bench in Anohana
I'm not sure if it is supposed to be Hindi or Sanskrit(because both use devagiri script and the word is there in both the languages), The word is 'Dharmayug', which means the age of righteousness or somewhere along that.

Also the word is another word for Satyayug which is one of the 4 ages of the Hindu Mythology. More specifcally the first age. Age of truth.

Not sure as to why the creator put it though.