Rapid urbanisation, climate change, and groundwater over-extraction are pushing major global and Indian cities toward an urban water crisis.
- The emerging risk is not scarcity alone, but systemic urban collapse when water systems fail.
About Zero Day
- The Concept: The term “Zero Day” became famous after the water crisis in Cape Town, South Africa.
- Definition: It refers to the specific day when taps run dry, and water ceases to flow in a city.
- The New Reality: Zero Day is no longer a distant threat but a reality becoming manifest in various global capitals and major cities.
Global Examples of Urban Water Collapse
- Tehran – A Capital in Compulsion:
- The Crisis: Tehran, Iran’s capital, is under extreme water stress.
- Compulsory Relocation: The Iranian President has stated that relocating the capital is no longer an option but a necessity.
- Climatic Cause: Tehran relies on the Alborz Mountains for water from melting snow and glaciers. Global warming has reduced snowfall and caused glaciers to melt at irregular, rapid rates, disrupting the natural water cycle.
- Land Subsidence: As groundwater is depleted, the earth becomes hollow, leading to the ground sinking and buildings cracking, a process known as land subsidence.
- The “Band-Aid” Solution: Measures such as smart meters and reduced water pressure are described as putting a “band-aid on a cancer tumour”.
- Jakarta – The Sinking City:
- Relocation Underway: Jakarta is already shifting Indonesia’s capital to Nusantara.
- Groundwater Dependency: Only 40% of Jakarta’s population has access to piped water, while 60% rely on groundwater.
- Rapid Sinking: Due to massive groundwater extraction and rising sea levels, Jakarta is sinking by 15 cm every year, with some areas sinking by up to 28 cm.
- Deadline: Jakarta is expected to be completely submerged within the next 25 years.
The Crisis in India
- NITI Aayog Warning: A report by NITI Aayog indicates that 21 major Indian cities are under severe water stress, including Bengaluru, Hyderabad, Pune, Delhi, Chennai, and Shimla.
- Chennai’s Near-Zero Day: In 2019, Chennai experienced a near-zero-day situation, with water transported into the city by trains.
- Rise of the “Tanker Mafia”: In cities such as Delhi, the failure of 24×7 water supply has led to tanker mafias controlling water distribution in many areas.
Delhi and the Pollution of the Yamuna
- The Ammonia Problem: During festivals such as Chhath Puja, the Yamuna is often covered in white foam from ammonia released by untreated industrial waste and sewage.
- Treatment Failure: High ammonia levels make water impossible to treat even in modern plants, rendering it unfit for human consumption.
- Inter-State Dependency: Delhi depends on water (90%) from Haryana and Uttar Pradesh, and any breakdown in cooperation leaves the capital “thirsty”.
Ecological Drivers – “The Death of Spring”
- Seasonal Disruption: Climate change has led to the “Death of Spring”, where traditional seasons are blurred by extreme weather events.
- Glacial Retreat: Like Tehran’s dependence on the Alborz, India’s perennial rivers, such as the Ganga, Yamuna, and Satluj, depend on Himalayan glaciers that are melting rapidly, while snowfall is decreasing.
Current Mitigation and Technology
- Atal Bhujal Yojana: Focuses on community participation and teaching citizens “water budgeting” to manage groundwater as a shared resource.
- Piezometers: Technology used to measure groundwater pressure and depth in real time to support scientific management.
- Efficiency Measures: Promotion of drip irrigation to reduce agricultural water waste.
- Exploration of river-linking projects, such as the Ken–Betwa link, despite associated ecological risks.
Conclusion
The experiences of Tehran and Jakarta underline that without urgent, ecological, and governance-driven water reform, Indian cities risk crossing irreversible Zero Day thresholds.
10 Feb 2026
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