  The pseudorapidity asymmetry and centrality dependence of charged hadron
spectra in d+Au collisions at $\sqrt{s_{NN}}=200$ GeV are presented. The
charged particle density at mid-rapidity, its pseudorapidity asymmetry and
centrality dependence are reasonably reproduced by a Multi-Phase Transport
model, by HIJING, and by the latest calculations in a saturation model. Ratios
of transverse momentum spectra between backward and forward pseudorapidity are
above unity for \pT below 5 GeV/$c$. The ratio of central to peripheral spectra
in d+Au collisions shows enhancement at 2 $<$ \pT $<$ 6 GeV/$c$, with a larger
effect at backward rapidity than forward rapidity. Our measurements are in
qualitative agreement with gluon saturation and in contrast to calculations
based on incoherent multiple partonic scatterings.
