it's far away in the pokemon world
not our world
The only difference in the Pokemon World and the real world is the Pokemon. They have mentioned many other countries in the games and Anime. They have mentioned both north and South America, they have mentioned Antarctica, the north pole and a few more.
EDIT: Here is alot of proof.
Arcanine's FireRed Pokédex entry states that it is mentioned in Chinese legends.
Parasect's Pokédex entry mentions its spores are used in medicine in China.
Regice's Emerald Pokédex entry mentions Antarctic ice.
Upon defeating Fisherman Bronson in the Sinnoh Battle Tower, he will say, "Why the emperor of fishing? It's an ancient Chinese legend..."
In Pasta La Vista!, an ad on a book mentions "Chinese Noodles."
Lt. Surge is known as "The Lightning American!"
Mew was originally discovered in the jungles of the South American country Guyana. This is mentioned in logs inside of Cinnabar Island's Burned Mansion.
Xatu's FireRed and Silver Pokédex entries mentions its association with mysticism in South America.
Poliwrath's Ruby, Sapphire, Emerald, Diamond, Pearl, and Platinum Pokédex entries mention its ability to swim the Pacific Ocean. Also, it is to be noted that the direction of its spirals depends on their geographical location.
Delibird's Ruby, Sapphire and Emerald Pokédex entries explain that a Delibird helped a famous explorer reach the top of Mt. Everest.
Silph Co.'s Tiksi Branch is in Russia.
In Mewtwo Strikes Back, Team Rocket are disguised as vikings. In the English dub, Brock says that he didn't know that vikings still existed and Ash replies that they come from Minnesota. This is clearly a reference to the Minnesota Vikings football team.
Ponyta's Pokédex entries mentions that it can clear Ayers Rock and jump over the Eiffel Tower in one leap.
A Guitarist that can be battled in the Battle Frontier mentions that his guitar is actually a Japanese instrument.
In School of Hard Knocks, Misty mentions wanting to go to Paris.
In Wherefore Art Thou, Pokémon?, Misty described the town like being in 'Merry Old England,' in which it could possibly be based on Tudor Time Stratford-Upon-Avon. It is also the same historic town where the story's inspirational Author, William Shakespeare was born.
In The Scheme Team, Jessie talks about Antarctica, the place where their next assignment is located. It should be noted that this was dub-added.
In Celebi: Voice of the Forest, Meowth asks if they saw Vicious in a Mexican wrestling movie.
In the English version of The March of the Exeggutor Squad, Melvin says he wanted to make it to Las Vegas. It should be noted that he said that he wanted to make it to Broadway in the Japanese version.
In the first movie, Meowth mentioned that they lived on the same Earth (although he may have been referring to the soil rather than the literal planet Earth).
In The Ninja Poké-Showdown, James says that the Fuchsia Gym looks like a Japanese restaurant.