Answer:
Water shortages are caused by climate change, such as altered weather patterns including droughts or floods, increased pollution, and increased human demand and overuse of water. A water crisis is a situation where the available potable, unpolluted water within a region is less than that region's demand.
Step-by-step explanation:
Some places may not have access to water either. For example Nigeria don't have access to drinking water or a sanitation system for the water that is their water shortage crisis. A place may have also had a river or stream that dried up, so it's not so much of the whole world has a shortage it's more of that one or more places seperate have a water shortage.
Hope this makes sense, GretaVanFleetRocks