Taanka

Geography glossary

Also called: Tanka · Topic: Water Resources of India: Availability, Use and Conservation · NCERT: Class 7, Ch 1 "Geographical Diversity of India"; Class 10, Ch 3 "Water Resources"

Meaning

A taanka (also spelt tanka) is an underground tank built inside a house or its courtyard in arid western Rajasthan, mainly in Bikaner, Phalodi and Barmer. Rain falling on the sloping roof flows down through pipes into this tank and is stored.

It matters because it shows how people adapted to the Thar Desert, where rain is scarce and the sun is hot. The stored water, called palar pani, lasts until the next rains, so it was a lifeline for families through the dry summer.

Explanation

How a taanka works (rain → roof → tank)

Collection: rain falls on the sloping roof of the house.
Carrying: the water runs off the roof into pipes.
Storage: the pipes lead into an underground tank in the main house or the courtyard.
The first-rain rule:
The first rain is let go and is not stored.
This first rain washes dust off the roof and out of the pipes.
Only the later, cleaner rain goes into the tank.
Result: the stored water is called palar pani, which means the purest form of natural water. It lasts until the next rains.

Why the tank is built underground

Less evaporation (water turning into vapour and escaping into the air):
The Thar is a hot desert.
Open water would quickly be lost to the sun and the dry air.
A covered tank below ground cuts this loss.
Clean water: the cover keeps out dust, sand and dirt.
A cool home:
The underground rooms next to the tank stay cool.
Families use these rooms in summer to escape the heat.

Size and parts

Roof catchment: the sloping roof is the area that catches the rain.
Pipes: carry the water down to the tank.
Underground tank: stores it. NCERT gives one taanka in Phalodi as 6.1 m long, 4.27 m wide and 2.44 m deep.
Type: a household system. Each family owns and uses its own taanka. A kund, by contrast, is a community pit.

Conditions it needs

Very low rainfall: western Rajasthan falls in the zone that gets below 50 cm of rain a year.
No perennial water (water that is available all year): there are no year-round rivers nearby and little good groundwater.
Hot, dry climate: water stored in the open would evaporate fast, so it has to be stored underground.
Sandy soil: rain soaks in quickly and cannot be held on the surface. It has to be caught where it falls, on the roof.

Where it occurs

India: houses and courtyards in Bikaner, Phalodi and Barmer, in the arid Thar Desert of western Rajasthan.
Same region, related systems: the kund (open ground near Thar villages), the khadin (Jaisalmer) and the johad (Alwar, eastern Rajasthan) also deal with scarce rain.
Decline:
The Indira Gandhi Canal brought perennial water to western Rajasthan.
After that, people used their taankas less.
Some households still keep theirs because they prefer the taste of the water.
Revival context:
Jal Shakti Abhiyan: Catch the Rain began on 22 March 2021. Its theme is "Catch the rain, where it falls, when it falls", which is the idea behind the taanka [2].
Its main tasks include rainwater harvesting and the renovation of traditional and other water bodies and tanks [2].

Don't confuse with

Kund (kundi): a community pit in open ground near Thar villages. A saucer-shaped catchment (ground sloping towards the centre) feeds a covered, circular underground pit. A taanka is a household tank fed by a roof.
Khadin (Jaisalmer): runoff farming. An earthen embankment across the bottom of a slope holds water so the soil stays moist for a crop such as wheat. The khadin waters fields. The taanka stores drinking water.
Johad (Alwar): a crescent-shaped earthen check dam or pond (a small barrier that slows water so it soaks into the ground). Its aim is to recharge groundwater. A taanka keeps water stored, sealed off from the ground.
Virda (Rann of Kutch, Gujarat): shallow wells dug by Maldhari herders. Fresh rainwater floating on salty groundwater is drawn from them. A virda takes water from the ground. A taanka is filled from the roof.

Prelims Hooks

Taanka → Bikaner, Phalodi, Barmer (Rajasthan). Do not mix it up with Khadin → Jaisalmer or Johad → Alwar.
Palar pani = rainwater stored in a taanka. It means the "purest form of natural water".
The first rain is let go to clean the roof and pipes. Only later rain is stored.
Source of water: rain from the sloping roof, carried by pipes. It is not river water, floodwater or groundwater.
NCERT size example: a taanka in Phalodi measured 6.1 m × 4.27 m × 2.44 m.
Trap: taanka = household tank; kund = community pit. Their use fell after the Indira Gandhi Canal brought perennial water.

Mains Points

Fitted to its place (GS-I: how geography shapes human adaptation):
Little rain, sandy soil and a hot sun meant water had to be caught on the roof and stored underground.
This cut evaporation and kept the water clean.
It is low-cost and uses little energy. No large project for the whole country can match local conditions this well.
Why it declined (GS-III):
State-built canals and tubewells, such as the Indira Gandhi Canal, replaced household and community systems.
Rural areas began to depend on distant water sources and on overused groundwater, so drought hits harder.
Policy response and way forward (GS-III):
JSA: Catch the Rain (2021) promotes rainwater harvesting and the renovation of traditional water bodies [2].
The Jal Jeevan Mission (2019) needs reliable water sources to keep its rural taps running. Roof-based storage like the taanka can help with this.
The way forward is to promote rooftop harvesting with taankas in desert homes and to use them alongside canal supply, not replace them with it.

Related concepts

Hydraulic heritage and traditional water harvesting

Sources

1Class 7, Ch 1 "Geographical Diversity of India"; Class 10, Ch 3 "Water Resources" (primary)
2PIB document, Jal Shakti Abhiyan: Catch the Rainstatic.pib.gov.in · tier 1