We establish a cutting lemma for definable families of sets in distal
structures, as well as the optimality of the distal cell decomposition for
definable families of sets on the plane in $o$-minimal expansions of fields.
Using it, we generalize the results in [J. Fox, J. Pach, A. Sheffer, A. Suk,
and J. Zahl. "A semi-algebraic version of Zarankiewicz's problem"] on the
semialgebraic planar Zarankiewicz problem to arbitrary $o$-minimal structures,
in particular obtaining an $o$-minimal generalization of the
Szemer