Question

reasons for chennai floods

Answer 1

pollutions and moonson seasons

Answer 2

Apart from the heavy rain-fall received in the year (2015), Chennai already had been severely affected that was undetected. This was unknown to most of them as they were living over it. The civilization that grew rapidly which leaded to settle over dried up ponds in Chennai.

The people who came into Chennai with hope, job and money started settling in those area without knowing that they are landing in an over night disaster which they cannot get to safer place.  

As the rainfall increased as never before, it started filling over all the water bodies in and around Chennai, when the limits reached filled-up ponds broke and came into the city where the ponds existed.  

These caused the Chennai floods 2015.