Groundwater contamination in India is a critical issue affecting millions, driven by both natural and human-induced factors. Below is a comprehensive overview based on recent data:

• Widespread Issue: A 2023 Central Ground Water Board (CGWB) report, released in December 2024, analyzed 15,259 groundwater samples, revealing that nearly 20% exceeded permissible pollutant limits.
• Affected Areas:
• Nitrate: Found in 56% of India’s districts (440 districts in 2023, up from 359 in 2017), exceeding the safe limit of 45 mg/L. Worst-affected states include Rajasthan (49% of samples), Karnataka (48%), and Tamil Nadu (37%).
• Fluoride: Affects 469 districts across 27 states, with high concentrations in Rajasthan, Haryana, Karnataka, Andhra Pradesh, and Telangana.
• Arsenic: Prevalent in 230 districts across 25 states, notably in Bihar, Uttar Pradesh, and West Bengal.
• Uranium: Detected in 6.6% of samples, with Rajasthan and Punjab reporting 42% and 30% of samples exceeding 100 ppb, respectively.
• Iron: Found in 13.2% of samples, impacting states like Bihar, Uttar Pradesh, and Odisha.
• Salinity: Affects over 2 million people, particularly in coastal regions like Gujarat (28 of 33 districts).
• Other Contaminants: Heavy metals like lead, mercury, cadmium, and chromium, as well as radioactive radon in areas like Bengaluru, are also concerns.

Causes

1. Natural (Geogenic) Factors:
   • High levels of arsenic, fluoride, iron, and uranium occur naturally in geological formations, exacerbated by over-extraction lowering water tables.
   • Example: Uranium in Rajasthan’s alluvial aquifers and Telangana’s granite rocks.
2. Human Activities:
   • Agricultural Runoff: Excessive use of nitrogen-based fertilizers and pesticides leads to nitrate and phosphate contamination. Consumption of chemical fertilizers increased by 16% from 2015-16 to 2020-21.
   • Industrial Discharges: Untreated effluents from industries, particularly in areas like Kanpur, introduce heavy metals. Over 2,000 industries operate without Effluent Treatment Plants (ETPs).
   • Urbanization: Poor waste management and untreated sewage contaminate groundwater, worsened by concretization reducing natural recharge.
   • Mining: Operations in states like Jharkhand and Chhattisgarh release heavy metals and uranium.
   • Over-Extraction: India extracts 241.34 billion cubic meters (bcm) of groundwater annually, with 11.23% of units overexploited, reducing recharge and concentrating pollutants.

Health and Environmental Impacts

• Health Risks:
• Nitrate: Causes methemoglobinemia (“blue baby syndrome”) in infants and reduced oxygen-carrying capacity in blood.
• Fluoride: Leads to dental, skeletal, and crippling fluorosis, affecting millions in states like Andhra Pradesh and Rajasthan.
• Arsenic: Linked to skin cancer, bladder, kidney, and lung cancers, and vascular diseases.
• Uranium: Causes kidney toxicity and increased cancer risk.
• Heavy Metals: Associated with neurological disorders, reproductive issues, and cancers.
• Environmental and Economic Impacts:
• Contaminated groundwater reduces agricultural productivity, leading to lower crop yields and food insecurity.
• Soil alkalinity and sodicity from high sodium and bicarbonate levels affect irrigation suitability.
• Economic losses impact India’s GDP, with potential 6% decrease by 2050 due to water scarcity.

Vulnerable Regions

• Rajasthan and Punjab: High uranium and nitrate contamination, linked to over-extraction and fertilizer use.
• Maharashtra, Telangana, Andhra Pradesh: Notable nitrate contamination, with Maharashtra having seven of the 15 most affected districts.
• Bihar, Uttar Pradesh, West Bengal: Significant arsenic and iron contamination.
• Coastal Gujarat: Severe salinity due to over-pumping and sea-level rise.
• Bengaluru: Contaminated by industrial effluents, sewage, and radon.

Current Efforts and Challenges

• Government Initiatives:
• Atal Bhujal Yojana: Reduced unsustainable groundwater levels from 23% to 19% across districts.
• Jal Shakti Ministry: Plans to deploy groundwater sensors for real-time monitoring of levels and contamination.
• National Aquifer Mapping (NAQUIM): Covers 25.15 lakh sq. km to map aquifers.
• Challenges:
• Systemic inertia and fragmented efforts hinder effective management.
• Inadequate enforcement of regulations like the Environment Protection Act (1986) and Water Act (1974).
• Unpredictable monsoons (e.g., 5.6% rainfall shortfall in 2023) reduce recharge.
• National Green Tribunal (NGT) expressed dissatisfaction with the Central Groundwater Authority’s response to arsenic and fluoride issues.

Proposed Solutions

1. Sustainable Agriculture: Promote precision farming, drip irrigation, and reduced fertilizer use to curb nitrate pollution.
2. Rainwater Harvesting: Encouraged as a cost-effective solution to dilute contaminants and recharge aquifers.
3. Infrastructure Investment: Build and maintain wastewater treatment plants to prevent untreated sewage contamination.
4. Decentralized Management: Empower local communities through Water User Associations (WUAs) to regulate extraction.
5. Blue Credit System: Offer financial incentives for rainwater harvesting and water-saving technologies.
6. Stricter Regulations: Enforce Effluent Treatment Plant (ETP) compliance and penalize non-compliant industries.
7. Groundwater Recharge Bill (2017): Enact legislation to mandate recharge systems in rural and urban areas.

Conclusion

Groundwater contamination in India, driven by over-extraction, agricultural runoff, industrial pollution, and geogenic factors, poses severe risks to public health, agriculture, and economic stability. While initiatives like Atal Bhujal Yojana show progress, urgent, coordinated action is needed to address systemic issues and ensure sustainable groundwater management.