Fractional power ratio, ΔC_ℓ/C_ℓ, from antipodal sky regions, computed from the SEVEM 143 GHz map before and after deboosting along the mean dipole direction for ℓ = 2 to 600. All spectra are evaluated on hemispheres using an apodized mask. The grey lines show the same quantity evaluated for each of the 500 FFP6 simulations along their respective asymmetry axes. The green band shows the 68% confidence region from these simulations.