Quantifying the Role of Groundwater, Agriculture, and Climate on India's Water Security: A Grey Relational Model Based on the Falkenmark Index

Currently, India is experiencing a prominent and serious water crisis characterised by extreme regional disparities which is essentially an outcome of the rising population growth, rampant urbanisation, and unsustainable extraction practices. This study employs the Falkenmark Index (2012–2024) alongside Grey Relational Analysis (GRA) to identify and rank the systemic drivers of per capita water decline. The findings of the study have reported a fall in water availability from 1,517 m³/person/year in 2012 to 1,318 m³/person/year in 2024, thereby pushing several geographical territories into water-stressed or water-scarce categories. GRA rankings indicate population growth (0.95) as the most influential driver, followed by groundwater extraction (0.85) and agricultural use (0.80), while pollution (0.70), infrastructure deficit (0.60), and monsoon variability (0.50) show moderate to lower impacts. Case studies from the states of Punjab and Haryana highlight the over-exploitation of groundwater for irrigation, while recurring water dispute between/among various states indicate governance challenges. These findings highlight the dominance of chronic stressors; population pressure, groundwater misuse, and irrigation intensity, over episodic climatic variability. The study contends that policy interventions must prioritise groundwater budgeting, crop diversification, micro-irrigation, wastewater reuse, and basin-scale governance to address the issues of per capita decline. By integrating GRA diagnostics with the Falkenmark framework, the analysis provides a decision-support tool for Integrated Water Resource Management (IWRM), aligning with national priorities and the Sustainable Development Goals (SDGs-6).