Here’s some explanations from the artist:
 

 
English Translation by Google:
 
Each character of a pony symbolizes a given voivodeship where there is sweetie belle it is a city of art but young, where rainbow dash there was a fast development of industry and the army in former Germany, fluttershy is Warmian-Masurian nature there is a lot of ecology and little pollution, snips and snails because there are two cities that they like and sometimes not, twilight because there is Warsaw and it is the most important voivodship, cheerileee because science has developed a little there and reminds me of the fral where she was from dashes, where apple bloom and applejack because there is a lot there farmers and apples are produced there a lot in Podlasie, for example, spitfires because there are a lot of aviators and aviation, babs seed, because there a minority want to disconnect from Poland, sandbar because there are new mountains there and there are a lot of foreigners there, like in young six, granny smith, because a lot of old people go there, rarity, because Krakow is a city of art and fashion, lyra and bon bon, because these two cities love each other more than they hate and pinkie pie, because there a lot of funny movies are made and generally there are also a lot of them.

@Background Pony Number 17  
Southeast Poland is considered as the most conservative and (relatively) less developed regions of Poland.
 
It can be shown on election maps, blue present conservative side.
 

I take it the southeast corner of Poland is the redneck part of the country?

I like this.

@Background Pony #37F6  
Znaczy sandbar na ślunsku?

Dlaczego Podlasie i cheerrilee? I sandbar na ślimaki?