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Groundwater, which is a precious and essential source of drinking water, must be cautiously maintained to maintain its quality under normal limits. In many parts of India, water available for industrial activities has reached a level of crisis. The Central Ground Water Board (CGWB) reports states that out of the total replenishable groundwater (431.42 billion cubic meters), the percentage of total replenishable groundwater in the Ganga Basin is 39.6% and the other four basins are the Godavari at 9.42%, Brahmputra (6.15%), Indus (6.14%), and Krishna at 6.12% having more than 5% of total replenishable groundwater resources in the country (Parmar 2017). India observed a 40% decline of groundwater level in recent years (2017–2018) – an unsustainable rate. If this continues, it is estimated that nearly 60% of groundwater resources will be in a critical state by the year 2030. The status of the groundwater level in different states of India is shown in Figure 3.2 for 2018.

Figure 3.2 Status of groundwater level in India in 2018.

(Source: Groundwater Year Book – India 2017–2018.)

Groundwater depletion happens when parameters (BOD, COD, TSS, TDS, nitrates, chlorides, fluoride, etc.) are altered by the addition or withdrawal of other compounds beyond their normal variations. The contact of a bore well or any other groundwater source with industrial effluent discharge can alter the quality of water. The effects of groundwater contamination by industry are outlined as follows (Gagan et al. 2016; Mali et al. 2015):

 Contaminated water with heavy metals or any other toxic chemical may cause health effects to consumers, such as arsenic poisoning, mercury poisoning, lead toxicity causes cancer, respiratory damages, liver damages, and kidney failure.

 Contaminated water also reduces crop yield and quality due to toxic chemicals, as various industries discharge partially treated or untreated effluent into agricultural fields which degrades soil quality.

 Consumption of these contaminated foods creates human health issues and food insecurity.

 Tannery effluents with improper treatment add chromium into the groundwater and surface water. This causes various diseases and environmental degradation.

 Sugar mill effluents have a higher number of suspended solids, dissolved solids, BOD, COD, chloride sulfate, nitrates, calcium, and magnesium. The continuous use of these effluents harms crops when used for irrigation. As a result, a higher number of various elements are deposited in the soil, causing pollution.

 Dumping of industrial discharge on any site causes leaching of heavy metals and toxic chemicals. This infiltrates through the soil profile into groundwater and hence contaminates groundwater quality.