What defines physical water scarcity?

Physical water scarcity is characterized by high demand for water that exceeds the available supply. This situation often occurs in regions where water resources are limited or difficult to access, particularly in arid or semi-arid environments where natural freshwater sources may not sufficiently meet the needs of the population or agricultural demands.

In areas experiencing physical water scarcity, the competition for water resources can lead to significant challenges for communities, agriculture, and industry. This definition aligns with the concept of physical water scarcity, as it directly implies a gap between water availability and the demands placed upon it, highlighting the stress on water resources in such environments.

The other options are related to different aspects of water issues but do not accurately define physical water scarcity. Low demand for water in arid environments does not align with the concept of scarcity, as scarcity is primarily about the inadequacy of supply relative to high demand. Inaccessible water sources due to pollution pertains more to environmental degradation rather than a shortage of water itself. Additionally, low population density does not necessarily lead to scarcity; it can coexist with abundant water resources, thus further distinguishing it from the characteristics of physical water scarcity.