Explanation:

Large and continuous supply of warm and moist air is the most important condition for formation of tropical cyclone. Where coriolis force is zero (like equator), tropical cyclones do not develop. An upper level outflow of air (and not inflow) helps in formation of tropical cyclone.

Ockhi originated near the south-western coast of Sri Lanka, and travelled very near the southern-most tip of the Indian mainland, along the coasts of Tamil Nadu and Kerala, towards the Lakshadweep islands, Maharashtra and Gujarat.
In India, cyclones are known to occur in both the Bay of Bengal and the Arabian Sea. The Bay of Bengal witnesses four times more cyclones than those experienced by the Arabian Sea. But the case of Ockhi is peculiar. The cyclone originated near the south-western coast of Sri Lanka and followed a very unique trajectory by travelling along the coasts of Tamil Nadu, Kerala and Lakshadweep islands, then it took north-easterly turn travelling along the coasts of Maharashtra and Gujarat. The cyclones in Maharashtra and Gujarat are not a common phenomenon. According to M. Rajeevan Nair, secretary, Earth Sciences, this is only the third time that a cyclone has taken such a unique route since 1891.

Second, Ockhi has originated very near to the equator. It had formed five degrees south. Usually, cyclones do not originate in the equatorial zone due to the earth’s rotation and shape. Cyclones tend to form at least seven degrees north or south of the equator.