Delhi's Groundwater Poses Severe Health Threat, Reveals Alarming CPCB Report
A shocking new report from the Central Pollution Control Board (CPCB) has revealed that Delhi is facing one of the most severe groundwater contamination crises in India. The study, released this month, identified dangerously high levels of uranium, lead, nitrate, fluoride and salinity in the capital's aquifers, creating long-term health hazards for millions dependent on borewell and hand pump water.
Uranium and Lead: The Silent Killers in Delhi's Water
The report highlights that Delhi has the third highest proportion of uranium-contaminated groundwater samples in the country, trailing only Punjab and Haryana. Uranium levels exceeded permissible limits in 13-15% of samples tested, raising serious concerns given the metal's well-documented links to kidney damage and cancer risks.
Even more alarming is Delhi's lead contamination scenario. The capital recorded the highest percentage of lead-contaminated groundwater samples in India during pre-monsoon season, with 9.3% of samples exceeding Bureau of Indian Standards (BIS) limits. This far exceeds contamination levels in Assam (3.23%) and Rajasthan (2.04%).
Lead is particularly dangerous as it's a neurotoxin that impairs cognitive development in children, increases blood pressure, affects kidney function and is classified as a probable human carcinogen. Medical experts emphasize that even low concentrations of lead are unsafe for human consumption.
Multiple Contaminants Create Perfect Storm of Health Risks
The groundwater crisis extends beyond heavy metals. The report identified elevated nitrate levels largely driven by anthropogenic sources, notably agricultural practices and improper waste disposal. Meanwhile, high fluoride concentrations were attributed to predominantly geogenic (naturally occurring) factors associated with water-rock interactions in crystalline aquifers.
Electrical conductivity (EC), an indicator of total dissolved solids and salinity, remains one of Delhi's major groundwater stress points. The capital showed 23.3% of samples exceeding EC limits in 2024, which dramatically increased to 33.33% in 2025 data.
Delhi's groundwater also reflected significant alkali and salinity hazards when assessed through Sodium Adsorption Ratio (SAR) and Residual Sodium Carbonate (RSC). The city reported one of the worst SAR figures nationwide – up to 179.8 at some locations, with 34.8% of samples exceeding permissible limits. For RSC, Delhi topped the country with 51.11% samples above the safety threshold.
Environmental Activists Sound Alarm, Demand Immediate Action
Environmental activists have termed these findings as evidence of a growing crisis linked to aquifer stress and unchecked borewell activity. Pankaj Kumar, a Delhi-based environmental activist, stated that contamination stems from over extraction of groundwater and boring activities.
Kumar emphasized that the most concerning indicators are the high uranium levels, electrical conductivity and SAR, noting that if SAR is too high, the water is not even good for industrial use, let alone other uses.
These concerns prompted Delhi-based civil society group Earth Warrior to write to Lieutenant Governor V K Saxena and Chief Minister Rekha Gupta demanding immediate public disclosure of groundwater quality data for all 5,500 tubewells and ranney wells operated by Delhi Jal Board (DJB).
The group highlighted that DJB supplies over 450 million litres per day of untreated or minimally treated groundwater directly into local networks. They've urged authorities to publish water quality test reports for every operational tubewell, disclose treatment methods used before supply, and release a time-bound action plan to achieve full compliance with BIS drinking-water standards.
The CPCB has recommended a combination of source protection, improved fertilizer management, targeted treatment technologies, strict regulation of industrial effluents and hotspot monitoring to contain the spread of contaminants. The board also emphasized the need for hydrogeochemical mapping, especially in cities like Delhi where multiple contaminants such as salinity, uranium, nitrate and lead overlap spatially.
