The world is facing an acute shortage of clean and safe freshwater. What are the alternative technologies which can solve this crisis? Briefly discuss any three such technologies citing their key merits and demerits.
Approach · directive: “what / discuss”
What it asks · Name alternative water technologies and evaluate three of them with merits and demerits.
It asks 2 things — answer each
- What: the alternative technologies that can address the freshwater crisis
- Discuss any three of them with their key merits and demerits
Open with · WHO and UNICEF (2025) report that 1 in 4 people, 2.1 billion, still lack safely managed drinking water, as pollution and climate change shrink the usable supply.
Cover
- Options: desalination, wastewater recycling, atmospheric water generation, managed aquifer recharge, rainwater harvesting, fog harvesting, solar stills.
- Desalination (reverse osmosis): drought-proof supply, as at Chennai's Minjur (2010) and Nemmeli (2013) plants; but energy-intensive, costly, and brine harms marine life.
- Wastewater recycling: Singapore's NEWater turns treated used water into ultra-clean reclaimed water from four plants; needs investment and public acceptance.
- Atmospheric water generators: draw water from humid air, useful off-grid; high energy use, low output and humidity dependence.
- Managed aquifer recharge: cheap, stores water underground; depends on geology and clean recharge water.
- Cross-cutting: pair technology with pricing, leak control and renewable power to keep costs and emissions down.
Close with · No single technology suffices; a portfolio built on reuse and recharge, with desalination as a coastal backstop, is the path to SDG 6.3 on recycling and 6.4 on water-use efficiency.
Add value (verified)
- WHO/UNICEF (2025): 1 in 4 people worldwide still lack safely managed drinking water.WHO — 1 in 4 people globally still lack access to safe drinking water (26 Aug 2025) ↗“Despite gains since 2015, 1 in 4 – or 2.1 billion people globally – still lack access to safely managed drinking water”
- Chennai's first desalination plant, 100 MLD at Minjur, was built as a drought-proofing measure.CMWSSB — Annual Performance Report (Chennai Metro Water) ↗“as part of drought-proofing measure and taking into account the long term drinking water requirements of the city, Government has invested in desalination plants. a) Minjur Desalination Plant Desalination plants play a vital role in fulfilling city’s water supply requirements. The first desalination plant with a capacity of 100 MLD at Minjur”
- Chennai's Nemmeli desalination plant became operational in 2013 with full central assistance.CMWSSB — Annual Performance Report (Chennai Metro Water) ↗“The plant became operational in 2013 and water from this plant is being supplied to the southern parts of Chenna”
- Singapore's NEWater recycles treated used water into ultra-clean reclaimed water; four plants operate.PUB Singapore — NEWater ↗“The NEWater process recycles treated used water into ultra-clean, high-grade reclaimed water, helping to close the water loop and strengthen Singapore's water resilience. Watch the video to discover how NEWater is produced through a rigorous three-step purification process. There are currently 4 NEWater plants in operation.”
- SDG 6.4: by 2030 substantially increase water-use efficiency across all sectors; SDG 6.3 seeks more recycling and safe reuse.UN Sustainable Development Goals — Goal 6 ↗“Target 6.4 By 2030, substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals and supply of freshwater to address water scarcity”
Question: UPSC's CS (Main) 2024, GS Paper III — paper ↗. Approach: Minimalist IAS, checked 3 Oct 2026 (how we verify) — UPSC publishes no model answers. ·
Model answer· 319words · Minimalist IAS
WHO and UNICEF reported in 2025 that 1 in 4 people, 2.1 billion, still lack safely managed drinking water, while pollution and climate change shrink what is usable. Technology can add new sources, but each comes with a price.
Alternative technologies that can address the crisis
New freshwater sources: Desalination; Wastewater recycling; Atmospheric water generation; Managed aquifer recharge; Rainwater and fog harvesting; Solar stills
- Fit to place: coasts suit desalination, cities suit recycling, humid off-grid areas suit air-to-water units, and permeable terrain suits aquifer recharge.
Desalination (reverse osmosis): merits and demerits
- Merits: a drought-proof supply for coastal cities; Chennai built its Minjur (100 MLD, 2010) and Nemmeli (2013) plants as a drought-proofing measure, and the technology is proven at scale.
- Demerits: energy-intensive and costly per litre; brine and chemicals harm marine life; membranes need imports and skilled upkeep.
Wastewater recycling: merits and demerits
- Merits: tertiary treatment turns sewage into water for industry, farms and even drinking; Singapore's NEWater recycles treated used water into ultra-clean reclaimed water from four plants, closing the water loop and cutting river pollution.
- Demerits: high capital and energy cost, pathogen and micro-pollutant risk if standards slip, and public reluctance to accept reuse.
Atmospheric water generation: merits and demerits
- Merits: draws potable water from humid air for off-grid, coastal and disaster settings without pipelines.
- Demerits: heavy power use, low output and dependence on humidity make it unsuitable for arid regions at scale.
Way forward
- Demand first: pricing, leak control and reuse mandates keep new sources from being wasted.
- Recharge before machines: managed aquifer recharge is the cheapest store where geology allows.
- Clean power: run desalination and recycling on renewables so water security does not raise emissions.
No single technology suffices. A portfolio built on reuse and recharge, with desalination as a coastal backstop, is India's route to SDG 6.3, which seeks to increase 'recycling and safe reuse globally', and SDG 6.4 on water-use efficiency by 2030.
Prepared by Minimalist IAS to the answer standard of Shivam Singh (mentor, 7 years) · facts checked against official sources (how we verify) · updated 3 Oct 2026. UPSC publishes no model answers: compare your structure and coverage with this, then write your own.
