(Image source from: Hindustantimes.com)

For many years, numerous families in Delhi have depended on borewells, tubewells, and hand pumps for their drinking water, which frequently comes straight from the source with minimal processing. This reliance highlights a crucial point: clean groundwater leads to healthy individuals. Recently, a water-quality assessment by the Central Ground Water Board (CGWB), published in late 2025, has raised serious concerns for the city. The findings show that 13-15% of water samples collected from various locations in Delhi contained uranium levels higher than acceptable standards. However, the issues don't end there. The same study identified additional harmful substances such as nitrate, fluoride, lead, high salt content, and increased levels of dissolved solids in a notable number of wells. Given the scope of the issue, with many tubewells supplying water to households daily, these results are worrying. Prolonged exposure to multiple pollutants can negatively impact kidney function, bone health, child development, and even elevate the risk of chronic diseases. As environmental advocates and health specialists stress, it is crucial to act wisely through testing, treatment, and open communication. Below is a summary of the CGWB report's findings, the significance of each contaminant, and tips on how to safeguard your family.

Uranium: A hazardous heavy metal with significant dangers: The report states that out of 83-86 locations tested in Delhi, 24 samples (approximately 13.35-15.66%) had uranium levels exceeding the safe limit of 30 parts per billion (ppb). This positions Delhi among the regions in the country with the highest uranium contamination, trailing only behind Punjab and Haryana. Elevated uranium levels in drinking water can harm kidney function, disrupt bone health, and potentially raise cancer risks over time.

Nitrate: Hidden but dangerous, particularly for babies: Many of the samples tested revealed nitrate (NO3-) levels that surpassed safe limits. The CGWB and experts believe this contamination likely results from runoff from agricultural fertilizers, waste disposal, and sewage seepage, which are all common in densely populated cities. High levels of nitrate in drinking water can lead to methemoglobinemia, also known as "blue baby syndrome," in infants, which can dangerously reduce their blood's oxygen capacity. For adults, consuming high amounts over time could affect blood chemistry and lead to long-term health issues.

Fluoride: Naturally occurring but harmful in large amounts: The report also found fluoride (F-) levels above the safe threshold in numerous samples. Unlike nitrate or uranium, fluoride contamination is typically geogenic, stemming from natural interactions between water and rock deep in aquifers, rather than human activity. While small amounts of fluoride may benefit dental health, excessive fluoride over many years can lead to dental or skeletal fluorosis, resulting in weakened bones, harmed joints, and damaged teeth.

Lead: Harmful Substance, Kidney-Straining Factor, Hidden Threat: Notably, the 2025 survey reveals that Delhi had the largest amount of lead-polluted groundwater in India prior to the monsoon. 9.3% of the samples went over safe levels. Lead is a strong neurotoxin. Prolonged exposure can hinder children's brain development, elevate blood pressure, harm kidneys, and is seen as likely to cause cancer in humans, indicating there is no "safe" level for exposure.

Saltiness, Solids in Water, Toughness: Water You Can Taste, But Might Not Drink Safely: Numerous groundwater samples in Delhi displayed high electrical conductivity (EC), which indicates the presence of dissolved salts and minerals. Approximately 23.3% of older samples (with a rising trend in the most recent survey) surpassed EC limits, indicating high salinity, total dissolved solids (TDS), and water hardness.

Though hard or salty water may not appear dramatically harmful, over time, it can stress kidneys, worsen high blood pressure, heighten dehydration risks, and make water unsafe for cooking, especially for babies, older adults, and those with chronic illnesses.

What makes the 2025 findings particularly alarming is the presence of multiple contaminants. Many wells contain not just one pollutant, but two, three, or more. Picture drinking water with increased levels of uranium, nitrates, and lead, along with a high mineral content. The combined impacts can amplify risks such as kidney stress, bone issues, developmental problems, and even cancer over extended periods.

Groundwater specialists, environmental researchers, and the CGWB agree that the water issues faced by Delhi result from a mixture of natural geology, human influences, and excessive extraction:

Aquifer geology and natural water-rock interaction: Lots of aquifers in Delhi flow through rock layers rich in minerals. As water flows through these rocks, it absorbs substances like uranium, fluoride, and other naturally occurring compounds.

Excessive groundwater extraction: Over-pumping has significantly dropped the water level. Consequently, deeper aquifers, which generally contain more heavy metals and salts, are being drilled into more frequently. This increases the likelihood of pollutants entering water sources.

Pollution accumulation from fertilizers, sewage, and waste leakage: Nitrate and lead pollution are commonly connected to fertilizer runoff, poor waste disposal, untreated sewage invading the soil, or ineffective sanitation. In a crowded city, this type of pollution can seep into the ground and eventually reach aquifers.

Salt and mineral accumulation due to natural salts and overuse, particularly in dry or semi-dry areas. High salinity was especially noted in the western and north-western regions of Delhi.

The CGWB's 2025 groundwater-quality report serves as more than just a technical document; it is a warning to the people of Delhi. The risks from uranium, nitrate, fluoride, lead, and salinity, which were once isolated threats, are now merging in the city's aquifers. The reality that 13-15% of wells surpass safe uranium levels, along with many others showing unsafe levels of additional toxins, should change our perception of "tap water."

For countless households that depend on tubewell and borewell water, relying on untreated, unfiltered resources, the danger is significant. However, there is a solution available through consistent testing, effective filtration, public openness, and sustainable water management. Drinking water should provide nourishment, not harm. With increased awareness, united efforts, and the right protections in place, Delhi can still guarantee safe water for its residents.