  The nonlinear effect of gluon depletion in the collision of large nuclei can
be large. It is due to multiple scatterings among comoving partons initiated by
primary scattering of partons in the colliding nuclei. The effect can give rise
to substantial suppression of $J/\psi$ production in very large nuclei, even if
the linear depletion effect is insignificant for the collisions of nuclei of
smaller sizes. This mechanism offers a natural explanation of the enhanced
suppression in the Pb-Pb data recently observed by NA50.
