During the electrolysis of fused $\mathrm{NaCl},$which reaction occurs at anode

Cathode: Reduction

${\mathrm{Na}}^{+}+1{\mathrm{e}}^{-}\to \mathrm{Na}$

Anode: Oxidation

${\mathrm{Cl}}^{-}\to \frac{1}{2}{\mathrm{Cl}}_2+{\mathrm{e}}^{-}$

During electrolysis of NaCl, chloride ions are oxidized at anode and it is called oxidation