Prague gets quite cold in the winter, and so those elephants probably spend all night and at times all day standing on concrete and locked in those tiny quarters. Northern zoos all over the world really should have larger indoor rooms for their animals.
Yeah, the plight of indoor husbandry. Another reason why the extinction of the Woolly mammoth really is a loss; would have been an excellent alternative in northern zoos, and zoofans would have another species to raise to "holy cow" status...
As far as I know, there are plans to improve the housing conditions of Prague's elephants and hippos in the near future.
The elephants can take about 10 steps forward, turn around and then take 10 steps backwards. If the weather is nasty outside, which it would certainly be in Prague in the dead of winter, then the elephants can stand on that tiny slab of concrete for weeks on end. Pleasant surroundings?