Key Points

Three-fourths of the Earth's surface is water, but only a small portion is freshwater. This freshwater is a renewable resource because it is continually renewed and recharged through the hydrological cycle.

Water scarcity is the shortage of water, which can be caused by over-exploitation, excessive use, and unequal access. It is not just limited to regions with low rainfall.

Key causes include large and growing populations, rising demand for water in agriculture and industries, and increasing urbanization. Irrigated agriculture is the largest consumer of water.

Water scarcity can also be due to poor water quality. Pollution from domestic and industrial waste, chemicals, and pesticides can make available water unfit for human use.

Dams are built to impound river water for multiple uses like irrigation, electricity generation, flood control, and domestic water supply. Jawaharlal Nehru called them the 'temples of modern India'.

Dams can negatively affect the natural flow of rivers, cause sedimentation, harm aquatic life, and lead to the large-scale displacement of people and loss of livelihoods.

Multi-purpose projects often cause conflicts between states over the sharing of river water. The Krishna-Godavari dispute is a prominent example involving objections from Karnataka and Andhra Pradesh.

Rainwater harvesting is a traditional and effective method for water conservation that is both socio-economically and environmentally viable as an alternative to large dams.

Ancient methods in India include 'guls' or 'kuls' in the Himalayas for agriculture, and 'khadins' and 'johads' in Rajasthan to store water and moisten soil.

In arid regions of Rajasthan, houses traditionally have underground tanks called 'tankas' to store rooftop rainwater for drinking. This water is considered the purest form of natural water.

Tamil Nadu is the first state in India to make rooftop rainwater harvesting structures compulsory for all houses across the state, with legal provisions to punish defaulters.

In Meghalaya, a 200-year-old system uses bamboo pipes to tap stream and spring water, transporting it efficiently over hundreds of metres to irrigate plants at the root.

This central government scheme aims to improve groundwater management through community participation and behavioral changes in water-stressed states like Gujarat, Haryana, and Rajasthan.

The goal of this mission is to provide a safe and adequate supply of potable piped water to every rural household in India on a regular and long-term basis.