What defines water stress?

Water stress is defined as a situation where the demand for water exceeds the available supply, indicating a critical imbalance between how much water is needed for various uses (such as agriculture, industry, and domestic consumption) and how much water is actually available from natural sources. This condition can lead to scarcity, impacting not only the environment but also economic and social structures.

Factors contributing to water stress may include population growth, increased usage, climate change, and inefficient water management. In situations of water stress, communities might face shortages that could lead to conflicts, economic losses, and health issues due to insufficient access to clean water.

The other options don't accurately represent the concept of water stress. For example, having a water supply greater than demand would indicate water abundance rather than stress. A state of perfect water quality does not address the quantity issues involved in water supply and demand. Lastly, transporting water between river basins is a logistical solution that does not define the condition of water stress itself.