At the opening of the Upper Pierce Reservoir, Prime Minister Lee Kuan Yew had suggest that keeping the waterways of Singapore clean need to be a priority. There he set the target of a decade for the Ministry of Environment to clean up both the Singapore River and the Kallang River.
The rivers’ pollution had grown as for decades, the river residents had lived in unsewered premises and disposed their farm wastes into the river. These included families living on bum boats, hawkers, squatters, pig farms and duck farms. At least 26,000 families and 2,800 cottage industries had to be relocated during this massive clean-up.