An engineer by training, Hari is a generalist problem-solver at heart, with a decade of rich and varied experience in sustainability and social impact. He has worked on clean energy product development & research, off-grid energy access, water in industry and agriculture, food-security and participatory governance and more. Some of these projects have been recognised globally for impact and innovation, including twice by the United Nations. Hari is also a member of the Smart Cities Working Group of the IET Future Tech Panel leading the Water twin initiative.
The clock is ticking. According to the Composite Water Management Index (CWMI) report released by the Niti Aayog in 2018, 21 major cities (Delhi, Bengaluru, Chennai, Hyderabad and others) were hurtling towards zero groundwater levels by 2020, threatening the water security of 100 million people , .
Excessive groundwater pumping, inefficient and wasteful water management, along with years of deficient rainfall, have resulted in 12 percent of India’s population already living under ‘Day Zero’ scenarios. By 2030, the country’s water demand is projected to be twice the available supply, with resulting severe water scarcity for hundreds of millions of people and an eventual six per cent loss in the country’s GDP .
While we face complex and challenging systemic problems related to water, climate change and other issues, new solutions based on emerging technologies are providing powerful tools that can work towards achieving sustainability in the Indian context. Digital Twins are part of an ongoing digital transformation, wherein tools and technologies are applied to create “maps” of data from physical objects . These “maps” can act as “compasses” to reveal the “status” of objects, devices, people etc., aiding process visibility, enabling real-time transparency, and even allowing for faults and trends to be predicted ahead of time!
The first Digital Twins served as an inexpensive means to simulate varying conditions for NASA rockets, but have since advanced technologically to support a plethora of applications  including intelligently optimizing office space usage, personalised patient healthcare, built environment etc. Digital Twins in the water domain have encompassed applications including municipal water systems, industrial water use, and urban flood resilience – all of which present significant opportunities in the Indian context for better water outcomes.
Valencia is a Spanish city known for its arts, sciences, futuristic architecture – and one of the world’s most advanced software systems for water management, that is considered by some to be the first ‘true’ Water Digital Twin , . In 2007, the city’s water utility invested in sensors and digitalization, which ended up saving EUR 7 million a year. This was re-invested into installing 700,000 smart meters across the city, allowing for large amounts of data to be acquired. Algorithms were then created that used the data to balance supply and demand, forecast energy costs for the next day etc. In 2014, the project was taken to the next level  with machine learning, Artificial Intelligence, Big Data, and advanced algorithms added.
A municipal Water Digital Twin of this type presents capabilities for optimal design of networks (pipes, valves etc.) for service quality constraints and even carbon footprint minimization; master planning for network extension, replacement and resilience; leak detection and pre-location; optimization of energy efficiency, water velocity, service pressure and other parameters; early warning and emergency response; and water quality prediction. These functionalities of the Water Digital Twin leverage machine learning and hydrological modelling on big data acquired from sensors over the Internet-of-Things (IoT).
Other types of water-related Digital Twins exist as well. For example, a South African study  describes one for optimizing the performance of a water bottling plant, and notes that properly designed Digital Twins are becoming essential in the Industry 4.0 paradigm for production systems. Indian industries are huge water-guzzlers, especially in peri-urban areas of cities, with a projected consumption of almost18% of total water use by 2050 . Further, India scores poorly in terms of industrial water productivity , and Indian industrial plants reportedly consume 2-3 times more water per unit of production that those in other countries . There is therefore great scope for improving industrial efficiency using Digital Twins integrating water-related metrics and modelling, especially given that that water is a shared resource in cities. Industrial water use has direct implications for urban communities, including those vulnerable to the effects of climate change, and deserves to be addressed by Digital Twins and emerging data-based technologies.
Improved industrial water efficiency also presents an economic benefit with the potential to far outweigh the costs – especially as the ‘true’ cost of saving a litre of processed water has been demonstrated to reach almost 100 times the ‘nominal’ cost of water  in some cases. This ‘true’ cost is currently unappreciated and ‘under the radar’ in the Indian context and has the potential to provide attractive returns-on-investment and outcome-based financing possibilities for Water Digital Twin technologies.
Finally, the time is ripe for the deployment of Digital Twin technologies in the Indian Smart Cities, which contain significant digital infrastructure that can and should be leveraged towards the effort of furthering water sustainability (SDG 6). For example, the India Urban Data Exchange (IUDX) envisions to ‘unleash the power of data for public good’ by acting as a trusted agent for multi-party data-exchange in Indian Smart Cities. Such platforms and digital marketplaces could facilitate creating and leveraging the models underpinning Water Digital Twins to create value for a wide range of stakeholders across society.
 ‘India’s water crisis: The clock is ticking’. https://www.downtoearth.org.in/blog/water/india-s-water-crisis-the-clock-is-ticking-65217 (accessed Oct. 12, 2020).
 N. Aayog, ‘Composite water management index-A national tool for water measurement’, Manag. Improv., 2018.
 S. Datta, ‘Digital Twins’, Apr. 2017, Accessed: Apr. 15, 2021. [Online]. Available: https://dspace.mit.edu/handle/1721.1/107989
 ‘Digital twin report.pdf’.
 ‘Valencia: sun, sea and Digital Twins’, Apr. 15, 2021. https://www.aquatechtrade.com/news/utilities/goaigua-digital-twin-valencia/ (accessed Apr. 15, 2021).
 ‘Jaime Barba: It’s time to learn from our mistakes’, Apr. 15, 2021. https://www.aquatechtrade.com/news/utilities/jaime-barba-digital-twin-model-for-water/ (accessed Apr. 15, 2021).
 G. A. Gericke, R. B. Kuriakose, H. J. Vermaak, and O. Mardsen, ‘Design of Digital Twins for Optimization of a Water Bottling Plant’, in IECON 2019 – 45th Annual Conference of the IEEE Industrial Electronics Society, Oct. 2019, vol. 1, pp. 5204–5210. doi: 10.1109/IECON.2019.8926880.
 U. A. Amarasinghe, T. Shah, and B. K. Anand, ‘India’s Water Supply and Demand from 2025-2050: Business- as- Usual Scenario and Issues’, p. 39.
 S. Aggarwal and S. Kumar, ‘Industrial Water Demand in India – Challenges and Implications for Water pricing’, 2011, pp. 274–284.
 ‘1. National-water-mission- water-use-efficiency.pdf’.
 K. Henderson, K. Somers, and M. Stuchtey, ‘Measuring the real cost of water’, p. 2.
CGWA: Central Ground Water Authority
DJB: Delhi Jal Board
Digital Twin: Digital Twin
F&B: Food and Beverages
IUDX: India Urban Data Exchange
MOHUA: Ministry of Housing and Urban Affairs
OPC: Open Platform Communication
R&D: Research and Development
SMU: SMART Manufacturing Unit
WDS: Water Distribution System
WDigital Twin: Water Digital Twin