Why won't any govt clean up the Cooum river?

With all the advancement, technology, industries, and obvious money showing in nice buildings, commerce, schools and colleges, IT and other businesses soaring, why in the world would the govt or private enterprise not clean up the Cooum river? It is an eye sore anywhere we go in the city and the metro railsystem runs its entire length. The place stinks and is obviously a health hazard, breeding ground for mosquitoes and other disease bearing pests. Why does the state and central govt ignore this huge open toilet wound in the middle of a metropolis?