Ground water contamination is the presence of certain pollutants in ground water that are in excess of the limits prescribed for drinking water.

Severity of groundwater contamination:

• According to the Composite Water Management Index developed by Niti Aayog, 70% of the water resources are identified as polluted. 
• A study, published in Environmental Science and Technology Letters, has found over 30 micrograms per litre (mcg/l) of uranium in parts of northwestern, southern and southeastern India, which can damage one’s kidneys.
• Arsenic contamination- West Bengal, Jharkhand, Bihar, Uttar Pradesh, Assam, Manipur and Chhattisgarh – have reported contamination level that is above the permissible limit of 10 micrograms per litre (µg/L.)
• Nitrate levels above 10 mg/L (10 ppm) in groundwater caused “blue baby syndrome” in several villages in Punjab.
• Many states have a high concentration of Fluoride, way above the permissible limit, in groundwater.
• Most of the Indian states report high salinity in groundwater.

Causes for groundwater contamination:

• Industries- Manufacturing and other chemical industries require water for processing and cleaning purposes. This used water is recycled back to water sources without proper treatment. Also industrial waste is dumped in certain areas, the seepage of which results in groundwater contamination.
• Agriculture- the fertilizers, pesticide and other chemicals used in growing plants contaminate groundwater. 
• Residential areas- These generate pollutants (microorganisms and organic compounds) for groundwater contamination
• Mining- Mine drain discharge, oilfield spillage, sludge and process water also contaminate groundwater.
• Coastal areas- Saltwater intrusion increases the salinity of groundwater in nearby areas.
• Excessive extraction- It increases the concentration of minerals in the extracted areas, thus making it contaminated.

Conclusion:

Recent decision of Central Ground Water Authority (CGWA) for industries to pay a water conservation fee (WCF) is a welcome step. It is very difficult and costly to treat contaminated groundwater. Hence, it is better to minimize the risk of groundwater pollution. Public awareness programs about the importance of groundwater and ways to minimize its contamination should be implemented.