BharatNotes Note: This chapter was removed from the NCERT curriculum in the 2022 rationalization. It is retained here because water resources, water scarcity, groundwater depletion, and water conservation are among the most important topics in UPSC GS1 (geography), GS2 (welfare schemes), and GS3 (environment).
Why this chapter matters for UPSC: Water — its cycle, scarcity, conservation, and governance — is consistently one of UPSC's most tested environmental topics. India faces severe water stress, groundwater depletion, and inter-state water disputes. This chapter's fundamentals directly connect to Jal Jeevan Mission, National Water Policy, and river basin management.
PART 1 — Quick Reference Tables
The Water Cycle
| Process | Description | Driven By |
|---|---|---|
| Evaporation | Water from oceans/lakes/rivers → water vapour | Solar heat |
| Transpiration | Water from plants → water vapour (through stomata) | Solar heat |
| Evapotranspiration | Combined evaporation + transpiration | Solar heat; measured in agriculture |
| Condensation | Water vapour → tiny droplets → clouds | Cooling of air at altitude |
| Precipitation | Water falls as rain, snow, hail, sleet | Gravity |
| Surface runoff | Rain flows over land → rivers → ocean | Gravity |
| Infiltration | Water seeps into soil → recharges groundwater | Gravity + soil permeability |
India's Water Resources — Key Data
| Resource | India's Status |
|---|---|
| Annual average rainfall | ~1,170 mm (varies enormously: Cherrapunji ~11,000 mm; Jaisalmer ~200 mm) |
| Total freshwater resources | ~1,869 BCM (Billion Cubic Metres) per year |
| Utilizable water resources | ~1,123 BCM |
| Groundwater | 433 BCM utilisable; ~62% used for irrigation |
| Major rivers | 12 major river systems; 7 interstate river disputes |
| Per capita water availability | ~1,486 m³/year (2021) — below 1,700 m³ = water stress threshold |
PART 2 — Detailed Notes
States of Water
Three states of water:
- Solid (ice): Below 0°C; water molecules in fixed lattice; less dense than liquid water (ice floats — crucial for aquatic life in cold climates)
- Liquid (water): 0°C to 100°C at standard pressure; molecules flow freely
- Gas (water vapour/steam): Above 100°C (boiling point at sea level); at lower altitudes (reduced pressure), water boils at lower temperatures (mountain cooking problem)
Why ice floats: Water is densest at 4°C — unique property. Below 4°C, ice expands as it crystallises. This is why ice floats, and why ponds freeze from the top down (not bottom up) — allowing fish to survive under the ice layer in winter.
India's Water Crisis
UPSC GS1 + GS3 — Water scarcity:
India faces a complex water crisis — the paradox being that India has 4% of world's freshwater but 18% of world's population.
Types of water scarcity:
- Physical scarcity: Not enough water (Rajasthan, Kutch, parts of Marathwada)
- Economic scarcity: Water exists but infrastructure to access it is lacking (parts of Northeast)
Groundwater crisis:
- India extracts more groundwater than any other country (~250 BCM/year)
- Over-extraction for irrigation (especially for water-intensive crops like rice and sugarcane in water-scarce regions — Punjab's groundwater depletion is severe)
- CGWB (Central Ground Water Board): 67% of India's blocks show some level of groundwater stress
- Water table dropping by 0.5–2 metres per year in many parts of Punjab, Haryana, Rajasthan, UP
Policy responses:
- National Water Policy 2012: Prioritises drinking water > agriculture > industry; advocates integrated water resource management
- Jal Shakti Ministry (2019): Merged Water Resources and Drinking Water ministries; single authority for water management
- Jal Jeevan Mission (2019–2026): Tap water to every household; 81.71% coverage (~15.82 crore of 19.36 crore households; March 2026). [Additional] JJM 2.0 (Cabinet approved March 10, 2026): Extended to December 2028; total outlay ₹8.69 lakh crore (Centre + States); focus shifting from infrastructure to service delivery (functional water supply, not just pipe connections).
- PM Krishi Sinchayee Yojana (PMKSY): "Har Khet Ko Pani" (water to every field) + "More Crop Per Drop" (micro-irrigation)
- Pradhan Mantri Jal Sanchay (PMJS): Water conservation
- Atal Bhujal Yojana (ABY): Groundwater management in 7 water-stressed states (UP, MP, Rajasthan, Maharashtra, Haryana, Gujarat, Karnataka)
Inter-state water disputes (major):
- Cauvery: Karnataka vs Tamil Nadu (Cauvery Water Disputes Tribunal)
- Krishna: AP, Telangana, Karnataka, Maharashtra
- Mahadayi: Goa, Karnataka, Maharashtra
- Ravi-Beas: Punjab, Haryana, Rajasthan
Rainwater Harvesting
Rainwater harvesting: Collecting and storing rainwater for later use — on rooftops (rooftop harvesting), in check dams, tanks, and percolation pits.
Traditional Indian water harvesting systems:
- Johad (Rajasthan): Community ponds for cattle and humans; revived by Rajendra Singh ("Waterman of India")
- Kund (Rajasthan): Underground cisterns for rainwater storage
- Stepwells (Vav/Baoli): Gujarat and Rajasthan; historical water storage + temperature regulation + social space (Rani ki Vav, Patan, Gujarat = UNESCO WHS)
- Ahar-Pyne (Bihar): Traditional irrigation channels
- Phad (Maharashtra): Community irrigation system
- Zabo (Nagaland): Integrated land-water management
- Kul (Himachal Pradesh): Diversion channels from glacial streams
Policy: Several state governments mandate rooftop rainwater harvesting for new buildings (Maharashtra, Tamil Nadu, Delhi). CGWB promotes Rainwater Harvesting Scheme.
Bangalore's solution: After severe water crisis (~2019), Bangalore implemented large-scale lake rejuvenation and rainwater harvesting — important case study.
PART 3 — Frameworks
Water–Food–Energy Nexus
A critical framework for UPSC Mains:
| Component | Link |
|---|---|
| Water | Required for food production (70% of water use is irrigation) |
| Food | Growing more food requires more water; some crops (rice, sugarcane) very water-intensive |
| Energy | Pumping groundwater requires electricity; hydropower requires water; thermal power needs cooling water |
| Conflict | Energy policy (more hydropower dams) affects water availability; agriculture policy (subsidised power → over-pumping groundwater) affects water tables |
[Additional] 14a. Types of Drought — Four Categories
The chapter discusses water scarcity but does not define "drought" precisely. UPSC Mains often distinguishes drought types for GS1 (geography) and GS3 (disaster management) questions.
Four types of drought:
| Type | Definition | Indicator | Time Lag |
|---|---|---|---|
| Meteorological drought | Rainfall significantly below normal for a season/region | IMD: drought declared when seasonal rainfall deficit ≥ 25% below Long-Period Average (LPA); moderate drought = 26–50% deficit; severe drought > 50% deficit | Immediate |
| Agricultural / Soil moisture drought | Insufficient soil moisture for crops to grow even if some rain occurs; crop failure risk | Soil moisture index; crop water stress; evapotranspiration deficit | 1–2 months after meteorological drought |
| Hydrological drought | Decline in surface water (rivers, lakes) and/or groundwater levels below normal | River flow; reservoir levels; groundwater table | Months to years after meteorological drought |
| Socioeconomic drought | Water shortage affects economic activity, food security, and human livelihoods | GDP impact; food prices; migration | Long-term consequence |
Why the types matter:
- India may have meteorological drought (below-normal monsoon) but NOT agricultural drought if water-efficient crops are grown or groundwater is available
- Conversely, hydrological drought can persist even years after good rainfall, because groundwater recovers slowly
- NDMA (National Disaster Management Authority) has separate drought management guidelines addressing all four types
India's drought-prone states: Rajasthan, Maharashtra (Marathwada, Vidarbha), parts of Madhya Pradesh, Odisha, Andhra Pradesh — subject to cyclical agricultural droughts
[Additional] 14b. Namami Gange — Cleaning India's National River
Ganga is India's National River (declared November 4, 2008, during PM Manmohan Singh's government). The Ganga basin covers ~26% of India's geographical area, supports ~50 crore people, and receives industrial effluent and untreated sewage from hundreds of cities along its 2,525 km course.
[Additional] Namami Gange Programme — GS3 (Environment/River Management):
Background: The Ganga Action Plan (GAP, launched January 1986 by PM Rajiv Gandhi) largely failed — insufficient funds, poor coordination, and continued untreated sewage discharge led to continued pollution despite ₹900+ crore spent by 2000.
Namami Gange:
- Launched: June 2014 by PM Narendra Modi's government
- Phase 1 budget: ₹20,000 crore (2015–2020)
- Phase 2 (Namami Gange Mission-II): ₹22,500 crore approved; extended to 2026
- Ministry: Ministry of Jal Shakti (Jal Shakti Mantralaya — created 2019 by merging Ministry of Water Resources and Ministry of Drinking Water & Sanitation)
- Implementing agency: National Mission for Clean Ganga (NMCG)
Progress (as of mid-2025):
- 173 Sewage Treatment Plants (STPs) commissioned, with combined capacity of 3,976 MLD (million litres per day) — NMCG / PIB, FY 2025-26
- NMCG target: cumulative STP capacity of 7,000 MLD by December 2026
- Out of 492 projects sanctioned, 307 completed and operational
- Industrial effluent treatment: Zero Liquid Discharge (ZLD) norms imposed on Ganga riverbank industries (tanneries in Kanpur, pulp and paper mills)
- Biodiversity conservation: River Dolphin (Gangetic Dolphin — national aquatic animal) populations monitored; Gangetic ghariyal conservation under Namami Gange
- Aviral Dhara (continuous flow) and Nirmal Dhara (clean flow): Two goals of the mission — ensure minimum environmental flow and reduce pollution load
Why Ganga remains polluted despite efforts:
- Population along Ganga grew faster than STP capacity additions
- Old STPs often run at 40–60% capacity (electricity costs, poor maintenance)
- Untreated sewage from small towns and drains not yet covered by STPs
- Industrial violations continue despite ZLD norms
- Agricultural runoff (pesticides, fertilisers) not captured by STPs
CPCB Water Quality Classification: CPCB designates rivers into quality classes A through E based on their "Designated Best Use":
| Class | Best Use | BOD Limit |
|---|---|---|
| A | Drinking water after treatment (high standard) | < 2 mg/L |
| B | Bathing (outdoor contact) | < 3 mg/L |
| C | Drinking water with conventional treatment | < 3 mg/L |
| D | Wildlife and fisheries | < 3 mg/L |
| E | Irrigation and industrial cooling | (pH and conductivity criteria; BOD not primary criterion) |
Ganga's current status: Many stretches near major cities (Kanpur, Allahabad, Varanasi, Patna) classify as Class D or worse — BOD exceeds 3 mg/L, indicating insufficient oxygen for aquatic life and unsafe for bathing without treatment.
BOD (Biochemical Oxygen Demand): Amount of oxygen consumed by bacteria to decompose organic waste in water. High BOD = high organic pollution = oxygen-depleted water = dead fish. It is the most widely used indicator of organic water pollution.
Exam Strategy
Prelims traps:
- India's per capita water availability is below the 1,700 m³/year water stress threshold (2021 data: ~1,486 m³)
- India is the largest groundwater extractor in the world (NOT China or USA)
- Rani ki Vav (Patan, Gujarat): UNESCO World Heritage stepwell — example of traditional water harvesting
- Rajendra Singh = "Waterman of India"; revived Johad in Rajasthan; Ramon Magsaysay Award winner
- Cauvery River: Originates in Karnataka (Talakaveri, Coorg) → flows through Tamil Nadu → Bay of Bengal; NOT originates in Tamil Nadu
Practice Questions
Prelims:
Which of the following is the correct order of water allocation priority under India's National Water Policy 2012?
(a) Drinking water > Agriculture > Industry
(b) Agriculture > Drinking water > Industry
(c) Industry > Agriculture > Drinking water
(d) Drinking water > Industry > Agriculture"Johad" is a traditional water harvesting system associated with:
(a) Rajasthan
(b) Gujarat
(c) Kerala
(d) AssamThe Atal Bhujal Yojana focuses on:
(a) Construction of dams
(b) Groundwater management in water-stressed states
(c) River linking project
(d) Drinking water supply in urban areas
Mains:
India faces both floods and droughts simultaneously. Critically examine the paradox and suggest solutions through integrated water resource management. (GS3, 15 marks)
Traditional water harvesting systems of India have a lesson for modern water management. Discuss with examples from different regions. (GS3, 10 marks)
