>>55920839Context clues. The Galaxy building is built in brick (the real life equivalent only appeared in 1888 after it got damaged in a fire) and the camera in the photog's shop are more like 1900's era cameras than those made prior to the turn of the century.
It also lines up with the original lore of pokémon shrinking only being discovered in 1925 with the invention of the pokéball happening soon after that.
