Key Findings 

• 71.7% of India's groundwater meets BIS standards but 28.3% of samples exceed limits for one or more parameters,
• Nitrate Contamination: Nitrate is most widespread pollutant nationally, with approximately 20% samples exceeding WHO and BIS limits(45 mg/L) ,followed by fluoride and salinity
  • It is largely attributed to anthropogenic sources, e.g. fertilizer use and sewage and animal waste seeping in groundwater.
• Uranium contamination: Samples with uranium levels above the safe limit of 30 ppb were found at 6.71% during the Pre-Monsoon and 7.91% during post-monsoon.
  • Punjab recorded  highest contamination, followed by Haryana and Delhi
• Salinity: Salinity (Electrical Conductivity,) is a critical issue in arid and semi-arid regions like Rajasthan and Delhi, exceeding limits in 7.23% of samples.,
• Fluoride -  8.05% of nationwide samples exceeded limit however it was predominantly geogenic (naturally occurring). Rajasthan showed highest contamination 
• Lead - Delhi recorded highest contamination.It can impair cognitive development , increases blood pressure, affect kidney and is classified as probable carcinogen
• Irrigation Suitability: The groundwater quality is largely suitable for irrigation purposes. The majority of samples, 94.30%, fall into the "excellent category”.
• Other Trace Metal and Geogenic Contaminations: Arsenic (especially in Ganga and Brahamaputra basin), Manganese (e.g., Assam, Karnataka, Odisha, Uttar Pradesh, and West Bengal) etc.