Contamination of ground water in Tamil Nadu

As a part of regular activity of ground water regime monitoring, Central Ground Water Board under Ministry of Water Resources carries out chemical analysis of ground water samples once a year. These samples are collected from the network of ground water monitoring wells during pre-monsoon period (April/May). As per the latest chemical quality data available with CGWB, out of 451 samples spread over all the districts of Tamil Nadu, high Chloride (>1000 mg/l) was encountered at 38 locations.