Question

why does Chennai face cyclone threat?

Answer 1

Because it is near the ocean

Answer 2

The answer is simple, Chennai is located in the heart of retreating monsoon. Chennai is one of the place which choking and drowning annually for a cyclone with different names.  

Chennai has expanded its area for many time. It is surrounded by vast wetlands that floods annually during monsoons. But, now the wet lands have been occupied by building and construction sites and become more vulnerable for cyclone floods frequently.

As previously said, Chennai  is located in the heart of retreating monsoon which carry more rainfall. From  2015 Chennai has ambushed with many cyclones every year until now. Occupied construction sites and poorly maintained drainage systems made the possibility of flooding even more terrible.