What spanish region does it most affect?

The question lacks context regarding what "it" refers to, but if discussing a significant issue such as climate change or economic challenges, one could say that the region most affected in Spain is often Andalusia. This southern region faces severe droughts, rising temperatures, and economic impacts due to its reliance on agriculture and tourism. Alternatively, if referring to political issues, Catalonia is frequently highlighted due to its push for independence and resulting tensions with the central government.