Water scarcity and its causes
A tap runs dry in the afternoon in a city that gets plenty of rain, while a village far away has a full well. Water is not short everywhere in the same way.
Water scarcity means not having enough usable water. About three-fourths of the earth is covered by water, but only a small part is usable freshwater, and it is renewed through the hydrological cycle (rain, run-off, groundwater).
Water scarcity and its causes
In the app you can move this figure with your finger.
Open in the appKey idea 1: Causes of scarcity — Rainfall varies by place and season, but scarcity is mostly caused by over-use, excessive use and unequal access among social groups. A large, growing population needs water for homes and for growing food. Irrigated farming is the largest user of water; wells and tube-wells in farms are lowering groundwater. Cities with plenty of water can still face a shortage.
- Easy: Rajasthan gets little rain, so water is short.
- Medium: Farmers digging many tube-wells make the groundwater level fall.
- Exam-type: A city beside a river still runs short of water because its population and demand have grown faster than supply.
Key idea 2: Industry, cities and quality — Industries use much water and power (much of it hydroelectric). Dense cities and housing societies pump groundwater and exhaust it. Scarcity can also come from bad quality: sewage, industrial waste, pesticides and fertilisers pollute water so it cannot be used safely.
- Easy: Factories use a lot of water.
- Medium: A river polluted by waste cannot be used for drinking even if it is full.
- Exam-type: A district has enough water by volume but it is full of chemicals. It still counts as water-scarce for drinking.
Scarcity is often caused by people (over-use, pollution, unequal access), not only by low rain.
Thinking scarcity happens only in dry regions. Water-rich cities can also run short.
Causes: Population, Irrigation, Industry, Pollution. Memory clue: "P-I-I-P".
Spot the difference
| Kind of scarcity | Cause | Example |
|---|---|---|
| Quantity | over-use, unequal access | falling groundwater in farms |
| Quality | pollution | river with industrial waste |
Practice questions
- 1Which sector is the largest user of water?
- 2Name the cycle that renews freshwater.
- 3Name one source of water pollution.
- 4Why can a city with plenty of rain face a water shortage?
- 5How do industries add to the water problem?
- 6What is meant by unequal access to water?
- 7Explain two ways in which farming leads to water scarcity.
- 8Explain how water can be scarce even when it is abundant.
Show answers (try them yourself first)
- 1Irrigated agriculture.
- 2The hydrological cycle.
- 3Industrial waste, sewage, pesticides or fertilisers.
- 4Its growing population and demand exceed supply.
- 5They use a lot of water and power, and release waste.
- 6Some social groups get far less water than others.
- 7Irrigation expands to grow more food, and farm tube-wells lower the groundwater level.
- 8If it is over-used, shared unequally or polluted, there is not enough usable water.
Water conservation and management
A family that fixes a leaking tap and reuses washing water spends less on water and wastes none. Small choices add up for a whole country.
Water conservation means saving water and using it wisely so that there is enough for health, food and livelihoods and nature is not harmed.
Key idea 1: Why it is needed — Conserving water protects health, ensures food security, keeps livelihoods and productive activities going, and prevents damage to natural ecosystems. Over-use and poor management impoverish the resource and cause ecological crises.
- Easy: Closing a tap while brushing saves water.
- Medium: Saving water keeps farms productive in dry months.
- Exam-type: If a town keeps over-pumping its wells, the water table falls and livelihoods suffer. Conservation prevents this.
Key idea 2: Government schemes — The Jal Jeevan Mission aims to give every rural household assured piped drinking water, at 55 litres per person per day. The Atal Bhujal Yojana (Atal Jal) works in 8,220 water-stressed gram panchayats of 229 blocks in 80 districts of seven states (Gujarat, Haryana, Karnataka, Madhya Pradesh, Maharashtra, Rajasthan, Uttar Pradesh) and tries to change attitudes from consumption to conservation. The need now is also to develop drought-resistant crops and dry farming.
- Easy: Jal Jeevan Mission is about piped water in rural homes.
- Medium: Atal Jal is meant for places where groundwater is over-used.
- Exam-type: A village gets a tap at every house at 55 litres per person per day. This is the aim of Jal Jeevan Mission.
JJM = piped water for rural homes; Atal Jal = groundwater management.
Mixing up the two schemes. One delivers water, the other manages groundwater.
JJM = Jal to Ghar (tap); Atal Jal = Bhujal (ground water). Memory clue: "Jeevan = Jar-to-home, Atal = Aquifer".
Spot the difference
| Scheme | Aim | Key number |
|---|---|---|
| Jal Jeevan Mission | piped water to rural homes | 55 litres per person per day |
| Atal Bhujal Yojana | manage groundwater in stressed areas | 8,220 panchayats |
Practice questions
- 1What does JJM aim to provide?
- 2How many litres per person per day does JJM target?
- 3Name one state where Atal Jal works.
- 4State two reasons for conserving water.
- 5What change in attitude does Atal Jal want?
- 6Why develop drought-resistant crops?
- 7Differentiate Jal Jeevan Mission and Atal Bhujal Yojana.
- 8Suggest three ways your family can save water.
Show answers (try them yourself first)
- 1Assured piped drinking water to every rural household.
- 255 litres.
- 3Gujarat, Haryana, Karnataka, Madhya Pradesh, Maharashtra, Rajasthan or Uttar Pradesh.
- 4To protect health and to ensure food security and livelihoods.
- 5From consumption to conservation and smart water management.
- 6They need less water, so farming survives in dry spells.
- 7JJM supplies piped water to homes; Atal Jal manages groundwater in water-stressed areas.
- 8Fix leaks, reuse wash water, and stop taps when not needed.
Dams and multi-purpose projects
A village tank keeps rainwater for the dry months. A dam does the same on a river, but on a much larger scale and for many uses.
A dam is a barrier across flowing water that stops or slows the flow, often forming a reservoir. A multi-purpose project uses the stored water for many things together.
Key idea 1: Old and new dams — Ancient India had stone dams, lakes and canals: Sringaverapura near Allahabad (first century BC) harvested Ganga flood water; Chandragupta Maurya's time saw many dams and lakes; the Bhopal Lake was built in the 11th century; Hauz Khas tank in Delhi in the 13th-14th century. Dams were once built only for irrigation. Today they also give electricity, drinking and industrial water, flood control, navigation and fish breeding.
- Easy: A dam creates a reservoir.
- Medium: Bhopal Lake is an old artificial lake.
- Exam-type: A dam on a river irrigates fields and also makes electricity. It is a multi-purpose project.
Key idea 2: Examples and a famous saying — The Bhakra-Nangal project (Sutlej-Beas) gives hydel power and irrigation. The Hirakud project (Mahanadi) joins water conservation with flood control. Jawaharlal Nehru called dams the temples of modern India because they link farming, village economy, industry and cities.
- Easy: Hirakud is on the Mahanadi.
- Medium: Bhakra-Nangal serves both power and irrigation.
- Exam-type: A project that controls floods and stores water for farms, like Hirakud, shows an integrated approach.
Dam = barrier; multi-purpose = many uses of the same water.
Thinking dams are only for irrigation. They now serve many uses.
Dam uses: Irrigate, Power, Drink, Flood, Boat, Fish. Memory clue: "I-P-D-F-B-F".
Spot the difference
| Project | River | Uses |
|---|---|---|
| Bhakra-Nangal | Sutlej-Beas | power, irrigation |
| Hirakud | Mahanadi | flood control, conservation |
| Sardar Sarovar | Narmada | irrigation, drinking water |
Practice questions
- 1What is a dam?
- 2On which river is Hirakud?
- 3Who called dams the temples of modern India?
- 4What is a multi-purpose project?
- 5Name two uses of dams today besides irrigation.
- 6Name two ancient water structures of India.
- 7Why did Nehru call dams the temples of modern India?
- 8Explain how Bhakra-Nangal is an example of integrated use.
Show answers (try them yourself first)
- 1A barrier across flowing water that obstructs or slows it, often making a reservoir.
- 2Mahanadi.
- 3Jawaharlal Nehru.
- 4A dam whose water is used for many purposes together.
- 5Electricity and flood control.
- 6Bhopal Lake and the Hauz Khas tank.
- 7They link agriculture, village economy, industry and cities.
- 8Its water is used for both hydel power and irrigation.
Problems of big dams and water sharing
When two neighbours draw water from one well, an argument can start if one takes more. States sharing a river face the same problem.
Big dams bring benefits, but they also cause ecological, social and political problems, so people questioned and opposed them.
Key idea 1: Problems caused — Damming changes the natural flow and traps silt, so reservoir beds fill with sediment and river habitats get poorer. Dams block fish from migrating to spawn. Reservoirs submerge vegetation and soil. Floodplains lose natural silt fertiliser. Some projects are blamed for earthquakes, water-borne diseases, pests and pollution. Dams meant to stop floods have sometimes caused floods through sedimentation. Irrigation has also pushed farmers towards water-hungry crops, causing salty soil.
- Easy: Silt collects behind a dam.
- Medium: A dam stops fish from reaching spawning areas.
- Exam-type: Floodplain fields below a dam get less silt, so their soil loses a natural fertiliser.
Key idea 2: Sharing and new efforts — Sardar Sarovar on the Narmada covers four states and will irrigate 18.45 lakh hectares in Gujarat and bring water to the drought-prone districts of Barmer and Jalore in Rajasthan. The Krishna-Godavari dispute arose because Maharashtra wanted to divert more water at Koyna, which could cut flow downstream in Karnataka and Andhra Pradesh. Pradhan Mantri Krishi Sinchayee Yojana aims at "har khet ko pani" (water to every field) and "per drop more crop".
- Easy: The Narmada has the Sardar Sarovar Dam.
- Medium: States can dispute river water when one diverts it.
- Exam-type: The PM Krishi Sinchayee Yojana slogan "per drop more crop" asks farmers to use water-saving methods.
Dams give benefits but also silting, displacement of habitats and disputes.
Thinking big dams control all floods. In heavy rain they have often failed.
Problems: Silt, Fish, Flood, Fields, Feud. Memory clue: "Silt, Fish, Flood, Fields, Feuds".
Spot the difference
| Benefit | Problem |
|---|---|
| irrigation and power | silting and lost fertility downstream |
| flood control | sometimes floods through sedimentation |
| water for dry districts | disputes between states |
Practice questions
- 1Name the dam built on the Narmada in Gujarat.
- 2What is the aim of "har khet ko pani"?
- 3Name one problem caused by big dams.
- 4How do dams affect fish?
- 5Why do floodplains lose fertility after a dam?
- 6What led to the Krishna-Godavari dispute?
- 7Explain three reasons why people oppose big dams.
- 8Why do water-intensive crops cause trouble in irrigated areas?
Show answers (try them yourself first)
- 1Sardar Sarovar.
- 2To give assured irrigation to every farm.
- 3Silting, displacement of habitats, or disputes.
- 4Dams block their migration to spawning places.
- 5Silt, a natural fertiliser, gets trapped behind the dam.
- 6Maharashtra diverting more water at Koyna, which reduces downstream flow.
- 7Poor sediment flow, damage to habitats, submerged land and soil, and induced diseases or earthquakes.
- 8They need heavy irrigation, which can make the soil salty.
Rainwater harvesting
On a rainy day, water runs off the roof and into the drain. Catching that water in a tank, as people have done for centuries, turns waste into supply.
Rainwater harvesting means collecting and storing rainwater, from roofs, fields or channels, for later use or to recharge groundwater.
Key idea 1: Traditional methods — In the Western Himalaya, people built guls or kuls (diversion channels). In Rajasthan, rooftop harvesting stored drinking water in underground tankas; the first spell of rain was left out to wash the roof, and later showers were stored, so it stayed pure till the next rain. Khadins in Jaisalmer and johads elsewhere in Rajasthan turned fields into rain-fed storage. In the Bengal floodplains, people made inundation channels.
- Easy: Tankas are underground tanks for drinking water.
- Medium: The first rain washes the roof and is not stored.
- Exam-type: A Bikaner house stores rooftop water in a tanka and keeps drinking water for the summer.
Key idea 2: Modern use — Shillong faces shortage though nearby Cherrapunji and Mawsynram have the highest rainfall; nearly every house there has rooftop harvesting, giving 15-25 per cent of its needs. In Gendathur (Mysuru), about 200 homes harvest rain; each house can collect about 50,000 litres a year. Tamil Nadu was the first state to make rooftop harvesting compulsory.
- Easy: Tamil Nadu made rooftop harvesting compulsory.
- Medium: Shillong uses rooftop harvesting to meet part of its needs.
- Exam-type: A village where about 200 homes collect rooftop rain is proud to be called rich in rainwater, as Gendathur is.
Catch rain where it falls; store it for dry months.
Storing the first rain too. The first spell is left out to clean the roof.
Match name to place: Guls = Himalaya, Tankas = Thar, Khadins = Jaisalmer. Memory clue: "G-H, T-T, K-J".
Spot the difference
| Method | Region | Use |
|---|---|---|
| Guls or kuls | Western Himalaya | irrigation channels |
| Tankas | Thar | drinking water |
| Khadins, johads | Rajasthan | farm storage |
| Inundation channels | Bengal floodplains | irrigation |
Practice questions
- 1What is a tanka?
- 2Which state first made rooftop harvesting compulsory?
- 3Where are guls or kuls used?
- 4Why is the first rain not stored in a tanka?
- 5Why does Shillong face water shortage despite being near Cherrapunji?
- 6What is palar pani?
- 7Describe how rooftop harvesting works with a tanka.
- 8Why is rainwater harvesting a good alternative to big dams?
Show answers (try them yourself first)
- 1An underground tank for storing rainwater.
- 2Tamil Nadu.
- 3The Western Himalaya.
- 4It washes the roof and pipes, so it is left out.
- 5Its demand is large and, despite heavy rain nearby, it lacks stored supply, so rooftop harvesting is needed.
- 6Rainwater, considered the purest natural water.
- 7Rain falls on the sloping roof, flows down a pipe and is stored in an underground tank.
- 8It is local, cheap and avoids flooding land and displacing people.