The ionospheric total electron content and equivalent slab thickness in the equatorial region around 75¿E have been studied. It is found that the slab thickness exhibits a strong latitudinal dependence with a maximum at the magnetic equator and a minimum around the crest of the F2 anomaly, indicating that the F region is thick near the equator and most skewed near the crest. The results are consistent with the electrodynamic drift and diffusion in the equatorial ionosphere.