Groundwater is the water below the surface of the land. It seeps in between rocks and particles of dirt and sand. People dig deep holes called wells to get the groundwater for drinking and other uses. The groundwater seeps into the well and humans pump it or haul it up in buckets to the surface.
Over the past ten years, northern India has lost as much as one foot of ground water a year. This is enough water to fill Lake Mead, the largest man-made reservoir in the United States, three times over!
Scientists know that this is happening from data gathered by the twin GRACE satellites.
Groundwater levels are falling fast in parts of northern India.
Between 2002 and 2008, more than 26 cubic miles of groundwater has disappeared in areas of Haryana, Punjab, Rajasthan and the nation's capitol territory of Delhi. Millions of people depend on this water supply. Its loss is serious, and researchers say the loss is almost entirely due to human activity.