Every year, the average rainfall in Mumbai is 4-5x that of Kolkata. Please understand this, there is no comparision. Period. The rainfall in Mumbai is bigger than that of ALL SEVEN CITIES PUT TOGETHER.
I REPEAT, THE NEXT SEVEN CITIES PUT TOGETHER!!
So, before rushing to condemn-please understand how the scale of rainfall is vastly more and therefore the challenges are far greater.
You cannot Mumbai's rainfall with that of any other city, becuase the rainfall is far far greater. Incomparably so. Therefore there is no comparision.
Hence, Mumbai floods are there because the rainfall itself is much bigger.