Arsenic problem in India is primarily due to overexploitation of groundwater in the affected areas.

The arsenic problem in India is a major public health concern, particularly in the states of West Bengal and Bihar. Arsenic contamination in groundwater has been identified as the primary cause of this issue.

Overexploitation of groundwater:
- Groundwater as a major source: Groundwater is a major source of drinking water in many parts of India, including the affected areas. The overexploitation of groundwater through excessive pumping has led to the lowering of water tables.
- Arsenic naturally present: In the affected regions, arsenic is naturally present in the geological formations. It gets dissolved in the groundwater, making it highly toxic when consumed.
- Increased concentration of arsenic: The over-pumping of groundwater has led to increased concentrations of arsenic in the water. As the water table drops, the arsenic-rich sediments come in contact with the remaining water, resulting in higher levels of contamination.
- Widespread drinking water contamination: Many people in these areas depend on groundwater for drinking and domestic purposes, leading to widespread exposure to arsenic-contaminated water.

Consequences of arsenic contamination:
- Health risks: Arsenic is a highly toxic element and long-term exposure to arsenic-contaminated water can cause various health problems such as skin lesions, cancers (including skin, lung, bladder, and kidney), cardiovascular diseases, and developmental issues in children.
- Social and economic impact: The arsenic problem has significant social and economic consequences. It affects the overall well-being of the affected population, leading to increased healthcare costs, loss of productivity, and decreased quality of life.
- Environmental impact: The overexploitation of groundwater also has adverse environmental impacts. It can lead to land subsidence, saltwater intrusion, and depletion of natural water sources, further exacerbating the arsenic problem.

Need for mitigation measures:
- Safe drinking water: The primary focus should be on providing safe drinking water to the affected population. This can be achieved through the implementation of arsenic removal technologies, such as activated alumina, iron removal filters, and reverse osmosis systems.
- Regulation and monitoring: There is a need for strict regulation and monitoring of groundwater extraction to prevent overexploitation and the resulting contamination.
- Public awareness and education: Creating awareness among the population about the risks associated with arsenic contamination and promoting hygiene practices can help in reducing exposure and preventing further health issues.

In conclusion, the arsenic problem in India, particularly in West Bengal and Bihar, is primarily due to the overexploitation of groundwater in the affected areas. Addressing this issue requires a multi-pronged approach, including the provision of safe drinking water, regulation of groundwater extraction, and public awareness campaigns.