(km.) north of the equator the winds are much weaker, in comparison. The stronger winds to the south pile up water where the winds are weak. ... The excess water flows eastward under the influence of the Earth's rotation, giving rise to the equatorial countercurrents.

What are equatorial currents caused by?

The current exists because the west- ward trade winds, in addition to driving divergent westward surface flow (upwelling is most intense at the equator), also maintain an eastward pressure force by piling up the warm surface waters in the western side of the ocean basin.

Why does equatorial counter current flow from west to east?

This is will decided by the direction of Earth's rotation. Earth rotates from west to east, so the piled up water due to earth's rotation will come down on its eastern side and will thus flow in the eastward direction.