Statement I:  Higher order ionisation constant ($\left({\mathrm{K}}_{{\mathrm{a}}_2},{\mathrm{K}}_{{\mathrm{a}}_3}\right)$ are smaller than the lower order ionisation constant (${\mathrm{K}}_{{\mathrm{a}}_1}$) of a polyprotic acid.
Statement II:  It is more difficult to remove a positively charged proton from a negative ion due to electrostatic forces.

Higher order ionization constants $\left({\mathrm{K}}_{{\mathrm{a}}_2},{\mathrm{K}}_{{\mathrm{a}}_3}\right)$ are smaller than the lower order ionization constans(${\mathrm{K}}_{{\mathrm{a}}_1}$) of a polyprotic acid. The reason for this is that it is more difficult to remove a positively charged proton from a negative ion due to electrostatic forces. 

This can be seen in the case of removing a proton from the uncharged ${\mathrm{H}}_2{\mathrm{CO}}_3$ as compared from a negatively charged ${\mathrm{HCO}}_3^{-}$.
Similarly, it is more difficult to remove a proton from a doubly charged ${\mathrm{HPO}}_4^{2-}$ anion as compared to ${\mathrm{H}}_2{\mathrm{PO}}_4^{-}$.