Why does the presence of a $-NO_2$ group at the $o,p$-positions increase the reactivity of haloarenes towards nucleophilic substitution reactions?

(N/A) The nitro group $(-NO_2)$ is a strong electron-withdrawing group due to its $-I$ and $-M$ (resonance) effects.
When present at the ortho or para positions,the $-NO_2$ group withdraws electron density from the benzene ring through resonance.
This creates a positive charge at the ortho and para positions,as shown in the resonance structures $(I)$ and $(II)$.
As a result,the carbon atom attached to the halogen becomes more electron-deficient (more positive),which facilitates the attack of a nucleophile (like $OH^-$).
Thus,the presence of $-NO_2$ groups at ortho and para positions makes the haloarene more susceptible to nucleophilic substitution.