Water stress occurs when the demand for fresh water exceeds the available amount during a certain period or when poor quality restricts its use. It is typically measured by per capita water availability, with levels below 1,700 cubic meters per person per year indicating stress.

In India, water stress is not a uniform phenomenon; it differs starkly across regions due to a combination of natural and man-made factors.

1. Rainfall and Geography: The primary reason for this variation is the uneven distribution of rainfall from the Southwest Monsoon. The arid and semi-arid regions of Western India, like Rajasthan and parts of Gujarat, receive scanty rainfall and face chronic water stress. In contrast, the Northeast and the Western Ghats receive abundant rainfall. Furthermore, North India is blessed with perennial Himalayan rivers like the Ganga and Brahmaputra, while Peninsular India relies on seasonal, rain-fed rivers, making it more vulnerable to dry spells.

2. Population Density and Urbanization: High population density in the Gangetic plains and in major urban centres like Delhi, Bengaluru, and Chennai places immense pressure on water resources, leading to over-extraction of groundwater and severe stress, despite being in relatively water-rich river basins.

3. Agricultural Practices: The agricultural heartlands of Punjab and Haryana, the epicentres of the Green Revolution, suffer from extreme water stress. This is not due to a lack of rainfall but because of the cultivation of water-intensive crops like paddy and sugarcane, leading to a drastic depletion of the groundwater table.