The world is facing an acute shortage of clean and safe alternative freshwater. What are the technologies which can solve this crisis? Briefly discuss any three such technologies, citing their key merits and demerits. (2024, 15 Marks)

Paper	GS Paper 3
Word Limit	250 words
Syllabus Topic	Science and Technology – Applications; Water Resources

Model Answer

Only a small share of Earth’s water is usable freshwater. NITI Aayog’s Composite Water Management Index (2018) said about 600 million Indians face high to extreme water stress. Technology can create new, safe sources of water.

Technologies That Can Help

Desalination, wastewater recycling, atmospheric water generators, solar stills, rainwater harvesting and advanced membranes like graphene oxide.

1. Desalination by Reverse Osmosis

• How: Seawater is pushed through a fine membrane that holds back salt (reverse osmosis).
• Merits: Almost unlimited source for coastal cities; Chennai runs plants at Minjur and Nemmeli.
• Demerits: High energy use and cost; salty brine discharge harms marine life.

2. Wastewater Recycling and Reuse

• How: Sewage is treated in stages to make water fit for industry, farms or even drinking.
• Merits: Reliable, local supply; cuts river pollution. Singapore’s NEWater is an example.
• Demerits: Public hesitation (“toilet to tap”); needs strong monitoring and sewer networks.

3. Atmospheric Water Generators (AWG)

• How: Machines cool humid air so water vapour condenses.
• Merits: Decentralised; useful for islands, remote posts and disasters.
• Demerits: High power per litre; little output in dry air.

Way Forward

• Run plants on renewable energy to cut cost and emissions.
• Combine technology with Jal Jeevan Mission, AMRUT 2.0 and water-saving habits.

Conclusion

No single technology can end the crisis. A mix of new supply, reuse and saving can secure clean water for all (SDG 6).

Related PYQs

• Why is the world today confronted with a crisis of availability of and access to freshwater resources? (2023)
• India is well endowed with fresh water resources. Critically examine why it still suffers from water scarcity. (2015)
• How and to what extent would micro-irrigation help in solving India’s water crisis ? (2021)