All the water was delivered years ago and there is no creation or destruction of water and still water scarcity exists because of the limited availability of usable and drinking water available.
Step-by-step explanation:
Our earth is covered be 71% of water and 29% of land. The water contained as water bodies majorly covers the earth's geography. Yet the amount of fresh water available is negligible and it is only 3%. This freshwater is available as rivers, lakes, groundwater and as glaciers. Around 2% is sealed in the Arctic and Antarctic poles as ice caps. Therefore only 1% is there for ready usage.
Water is used for almost everything from drinking to cleansing homes, vehicles, in agriculture etc. The sad part is that salt water from oceans and seas cannot be used for any of these. The available fresh water is not properly used by people. Contaminating and polluting water bodies further add up to water scarcity.