Union Minister Anupriya Patel on Friday said 20.71 per cent of groundwater samples analysed in 502 districts across 26 states/UTs were found to contain nitrate above the permissible limit of 45 mg/L.Quoting the Annual Ground Water Quality Report-2025, she said the maximum number of affected districts (48) lie in Uttar Pradesh followed by 44 districts in Madhya Pradesh, 38 districts in Tamil Nadu and 33 districts each in Maharashtra and Telangana.