Whilst blowing from HP to LP areas, the wind is deflected by coriolis force also called geostrophic force. It is caused by rotation of the earth.
It causes an air particle to be deflected to the right of its line of motion in the northern hemisphere, and to the left of its line of motion in the southern hemisphere. The force always acts at right angles to the line of motion of a particle.
Mathematically it can be shown that in the horizontal plane, with the xy coordinates aligned to north and east respectively, the geostrophic force per unit mass is 2Ωsinɸv where Ω is the angular velocity of the earth, ɸ the latitude, and v the speed of the air. It follows that at the equator sin ɸ = 0 and the force equals zero.