Certain visual and olfactory facets are instilled into the minds of the young. And there they remain stuck forever. So too with the Cooum. Nobody alive has seen it clean.
And hence every puddle of dirty water in Chennai is called the Cooum, though there are three distinct rivers running through Chennai and several canals with other names.
There is a constant and daily reminder too. Every afternoon, a stirring breeze from the bay, lifts the fetid odours of the river and unfurls it around the neighbourhood, thus reminding the citizens of Chennai of what a monumental mess they have made of their prime river.