The recent three-year WMAP data have confirmed the anomaly concerning the low
quadrupole amplitude compared to the best-fit \Lambda CDM prediction. We show
that, allowing the large-scale spatial geometry of our universe to be
plane-symmetric with eccentricity at decoupling or order 10^{-2}, the
quadrupole amplitude can be drastically reduced without affecting higher
multipoles of the angular power spectrum of the temperature anisotropy.Comment: 4 pages, 2 figures, minor changes, reference added, to appear in
Phys. Rev. Let
