Twin Cyclones
D. Indumathi, The Institute of Mathematical Sciences, Chennai
On May 8, 2022, the National National Oceanic and Atmospheric Administration (NOAA) photographed something unusual: two cyclones in the Indian ocean, one above the equator and the other below.
The twin cyclones were spinning at roughly the same distance from the equator, but in opposite directions. A cyclone’s winds spin counterclockwise in the Northern Hemisphere but clockwise in the Southern Hemisphere due to the Coriolis effect—a force driven by Earth’s rotation that deflects prevailing winds in one direction in the Northern Hemisphere and the opposite direction in the Southern Hemisphere.
In the northern Indian Ocean, Tropical Cyclone Asani advanced west-northwest on May 8 and had maximum sustained winds of 100-110 kilometers per hour as it moved across the Bay of Bengal. Asani rained over south India and finally dissipated over Andhra Pradesh and Orissa.
South of the equator, Tropical Cyclone Karim was roaming the open seas west of Australia. With winds peaking at the equivalent of a category 1 hurricane, the U.S. Joint Typhoon Warning Center expected Karim to weaken quickly. This is because cyclones that encounter high levels of wind shear weaken and dissipate (die down). The storm was far away from Australia, although it did affect the Cocos Islands, a chain of coral islands with a population of 600.
The path of both cyclones, ending with their current position marked by circles, is shown in the figure. The equator passes just below the tip of Malaysia (its capital, Kuala Lumpur, is seen marked in the picture). They both began around May 4, on either side of the equator, and drifted away from each other. By May 12, Asani had reached the coast of Andhra Pradesh, while Karim dissipated over the sea.

Coriolis force
You may have studied about a fictitious (imaginary) force called centriugal force. When a body is rotating, there is a force towards the centre called centripetal force. Since Newton's third law states that for every force acting on a body, there is an equal and opposite force that acts on the other body. This reaction force is called the centrifugal force. When the body stops rotating (centripetal force goes to zero), the centrifugal force vanishes as well. That is why it is called a fictitious force.
There is another fictitious force called coriolis force which occurs when a body is rotating, but we are viewing it from a frame where we are not moving along with it. In such a case, the coriolis force depends on both the velocity and angular velocity (speed of rotation) of the object. 
Remember that the Earth is actually rotating, and not the Sun. When viewed from above, the Earth is rotating to the east. Consider an object limited to the Earth's surface and moving northward in the Northern Hemisphere. Viewed from outer space, the object does not appear to go due north, but has an eastward motion (it rotates around toward the right along with the surface of the Earth). This apparent eastward motion is due to the coriolis force.
This force causes moving objects on the surface of the Earth to be deflected to the right (with respect to the direction of travel) in the Northern Hemisphere and to the left in the Southern Hemisphere. The horizontal deflection is greater as you approach near the poles, and decreases to zero at the equator.
We know that winds flow from areas of high pressure to low pressure. But because of the coriolis force, in a rotating system such as on Earth, they tend to flow to the right of this direction north of the equator (anticlockwise) and to the left of this direction south of it (clockwise). This effect is responsible for the rotation and thus formation of cyclones. You can immediately understand why cyclones can only form about 9 degrees latitude (north or south of the equator). The effect is very visible because cyclones are large systems, thousands of km across.

Could both have reached India?
No, we have just seen that due to the coriolis force, cyclones move away from the equator. So the paths of these two cyclones cannot cross. If you look carefully at the picture of the two cyclones, you will see that they are indeed rotating in opposite directions (look at the strands of cloud coming out from their centres), anticlockwise in the northern hemisphere, and clockwise in the southern hemisphere.
The coriolis force affects water currents as well. There are many well-known currents (like rivers) in the oceans. The gulf stream between US and Africa/Europe is the most famous: it brings warm water to Europe's coast, so that those otherwise cold countries are liveable.
Many of the ocean's largest currents circulate around warm, high-pressure areas called gyres. Again, the Coriolis effect creates a spiralling pattern in these gyres. Though not as significant as that in the air, the deflection caused by the Coriolis effect helps hurricanes to form. As a result, air travels clockwise around high pressure in the Northern Hemisphere and anticlockwise in the Southern Hemisphere. Air around low-pressure (as in cyclones) rotates in the opposite direction.
If you have visited a Science Museum, the Coriolis effect caused by the rotation of the Earth can be seen indirectly through the motion of a Foucault pendulum.
Image Credits: Wikipedia and NASA/NOAA: https://earthobservatory.nasa.gov/images/149812/twin-cyclones-in-the-indian-ocean