H2SO3 + 2 KMnO4 + 2 KOH → H2SO4 + 2 K2MnO4 + H2O
This is an acid-base reaction (neutralization): H2SO3 is an acid, KOH is a base.
This is an oxidation-reduction (redox) reaction:
2 MnVII + 2 e- → 2 MnVI (reduction)
SIV - 2 e- → SVI (oxidation)
KMnO4 is an oxidizing agent, H2SO3 is a reducing agent.