  In single crystals of 2H-NbSe2, we identify for the first time a crossover
from weak collective to strong pinning regime in the vortex state which is not
associated with the peak effect phenomenon. Instead, we find the crossover is
associated with anomalous history dependent magnetization response. In the
field (Bdc) - temperature (T) vortex matter phase diagram we demarcate this
pinning crossover boundary. We also delineate another boundary which separates
the strong pinning region from a thermal fluctuation dominated regime, and find
that PE appears on this boundary.
