• Natural Reasons: High levels of arsenic, fluoride, iron, and uranium exist naturally in geological formations, contaminating groundwater.
• Agriculture: Excessive use of fertilisers, pesticides, and herbicides leaches harmful chemicals into the water table.
• Industrial Waste: Release of untreated industrial effluents leads to seepage of heavy metals (lead, cadmium, mercury).
• Urbanisation: Leaky sewage systems and improper waste disposal in urban areas contribute to groundwater pollution.
• Saltwater Intrusion: In coastal areas, over-pumping of groundwater can cause saltwater from the ocean to infiltrate freshwater aquifers.
• Excessive Groundwater Extraction: In the Gangetic region, excessive extraction leads to Arsenic contamination.

Source: The Indian Express