Why is ozone a powerful bleaching agent?

It is highly electronegative Nascent oxygen Instability of molecule Large negative Gibbs energy

Nascent oxygen

Due to its ease in liberation nascent oxygen i.e. [O], ozone is a powerful oxidizing agent. Although, it is highly thermodynamically unstable and explosive due to large negative Gibbs energy, the ability of liberating nascent oxygen, it is considered to be one of most powerful bleaching agents.