India, March 24 -- More than half of the ground water samples tested between 2017 and 2022 were found to be unfit for drinking and pose a "serious risk" to public, said a report by the Comptroller and Auditor General (CAG) of India, raising serious concerns over the quality and safety of drinking water supplied in the national capital.

The report, tabled in Delhi Assembly on Monday, also flags glaring lapses in water testing, monitoring, and infrastructure including use of carcinogenic polyelectrolytes in treatment process.

The CAG report, titled "Functioning of Delhi Jal Board", said, "Quality testing of groundwater was carried out on 16,234 samples by the eight zonal laboratories of the DJB during the period 2017-18 to 2021-22. Out of...