The Indo-Gangetic Plain (IGP) is one of the most heavily farmed regions in the world. In recent decades, the widespread use of groundwater for irrigation and excessive nitrogen fertilizer application have caused serious environmental problems, including declining groundwater levels and nitrate pollution. This study focuses on the Hindon River Basin in the upper IGP, where we used an integrated eco-hydrological model to simulate water and nutrient movement between 2010 and 2022.

The results show that most of the water used in this basin goes into evapotranspiration, while groundwater pumping makes up a large share of water input. Several areas are experiencing long-term groundwater overdraft, especially during drought years. High nitrate concentrations, well above safe limits, were found in these areas, and levels did not improve even after water use declined during the COVID-19 pandemic. This indicates a delayed response of groundwater systems and long-lasting pollution.

Our study highlights the value of integrated models to identify pollution hotspots and test solutions like managed aquifer recharge and better fertilizer practices. The approach can be applied to other overexploited agricultural basins across South Asia.