Delhi's Water Crisis Will Keep Returning Till Yamuna's High Ammonia Isn't Solved

There is a limit to how much chlorine can be added as a disinfectant to treat high ammonia in untreated water.

For almost three weeks, Santosh Kumar's family of six in Uttam Nagar, a residential locality in West Delhi, faced a severe water crisis. “There was no water in the taps, and when it came, it was brown and sometimes carried a foul smell,” 39-year-old Kumar tells The Quint.

“We were scared to bathe or wash our dishes with that water, let alone drink it,” he adds. Kumar, who works as an insurance agent, says his family had to rely on municipal water tankers during this period.

The water crisis wasn't limited to Kumar's household or Uttam Nagar alone. Several neighbourhoods across Delhi struggled with erratic supply and contaminated water for a fortnight.

It all started in late January, when a spike in ammonia levels in the Yamuna River — one of Delhi’s primary sources of drinking water — disrupted operations at the Wazirabad and Chandrawal water treatment plants in North Delhi, among others.

The Delhi Jal Board said at the time that as the output was cut by 25-50 percent, the disruption would affect nearly two million people across North, Northwest, West, Southwest and Central Delhi, until 4 February.

The issue persisted for another week despite a Delhi Jal Board official telling The Quint that "all water treatment plants are now functioning normally". Yet, this wasn't the first time that high ammonia levels disruped Delhi’s water supply for an extended period.

Yamuna’s Ammonia Burden

The Yamuna River supplies about 40 percent of Delhi's drinking water, and yet, it is one of India's most 'toxic' rivers.

According to a December 2025 report jointly conducted by the Delhi government's Department of Environment and the Energy and Resources Institute (TERI), nearly 28 million gallons per day of untreated or partially treated wastewater enters the river through various stormwater and open drains. That's enough to fill roughly 42 Olympic-sized swimming pools.

In North Delhi, this water is treated at the Wazirabad and Chandrawal plants before being distributed to households. However, these plants often struggle to operate during elevated ammonia levels in the raw water supply.

The safe level of ammonia in drinking water is generally 0.5 mg/L, though some government standards allow up to 1.5 mg/L.

Speaking to The Quint, an official closely associated with the government’s water treatment operations, claimed that the "drinking water is drawn [for treatment] from upstream. The pollution enters downstream, after the river passes Wazirabad [treatment plant], so it shouldn't be conflated."

However, data from the government’s own water quality report indicate that ammonia levels and other quality concerns have been recorded upstream as well. For instance, the December 2025 report recorded ammonia levels of 27.4 mg/L upstream of Wazirabad in samples collected in December 2024.

As the river flows onward, it becomes more polluted with ammonia levels at around 30 mg/L found in downstream samples.

Moreover, the downstream samples, according to TERI, were taken before the Najafgarh drain joins the Yamuna, transferring more pollutants into the river.

In contrast, the Delhi Jal Board data for the same period recorded a maximum ammonia level of 5 mg/L upstream of Wazirabad—significantly lower than the government report, but still well above safe limits.

When levels exceed safe thresholds, ammonia can react with chlorine to form chloramines, which may cause skin irritation, and affect digestion and kidney function.

"High levels of ammonia in water gets converted to nitrites and nitrates which increases the acidity of the water, leading to the corrosion of distribution pipes. Excess nitrates is particularly harmful to infants as it is linked to blue baby syndrome (methemoglobinemia). In this condition, nitrites, derived from nitrates during digestion, interfere with the blood’s ability to carry oxygen," says Nitin Bassi, Fellow with the Sustainable Water Team at the Council on Energy, Environment and Water (CEEW).

Although the health risks of prolonged exposure to high ammonia levels are well researched, assessing their health impact is difficult, with no government data on fatalities directly linked to ammonia contamination in the city’s water supply.

Why Do Ammonia Spikes Keep Disrupting Delhi’s Water Supply?

According to the Delhi Jal Board official, water supply was cut after ammonia levels in the Yamuna rose beyond treatable limits. The official told The Quint that the supply was restored after the levels naturally declined due to dilution—an approach adopted during previous spikes as well.

• In December 2022, ammonia at the Wazirabad intake exceeded treatment capacity for months, peaking at 2.6 mg/L

• The levels rose to about 4.3 mg/L in January-February 2023

• Similar supply cuts followed in December 2023 when levels touched 2.3 mg/L

• In 2024, repeated spikes again disrupted operations at the Wazirabad and Chandrawal plants

• In May 2025, a Delhi Pollution Control Committee summary recorded ammonia levels of 5.7 mg/L

Explaining why treating high levels of ammonia in water is difficult, Bassi noted that the standard method involves adding chlorine to the water to counter it.

“If the levels of ammonia are higher than 1.0 ppm (part per million) or 1 mg/Litre of raw water, then this approach becomes ineffective, as the chloramines (formed from chlorine reacting with ammonia) may not kill bacteria efficiently, making water unfit for consumption”

Nitin Bassi

The Delhi Jal Board official told The Quint that when such spikes occur—like the one in late January—the treatment plants cannot handle the ammonia load. “In these situations, we have to hold the water without treating it, because it cannot be released as a potable supply. Once the water level rises or there is sufficient dilution, ammonia concentrations naturally drop,” he said.

Dilution can occur naturally through monsoon rains or when upstream states like Haryana release water into the Yamuna.

However, "Haryana can only release so much water to Delhi during the Late-winter, early-summer time because they are also short of water, so the water that is received through the Munak canal is reduced and we don't have enough water for dilusion.," explains Bassi.

Where Ammonia in the Water Comes From

According to experts, including assessments by the Central Water Commission, the primary contributors to elevated ammonia levels in the Yamuna include industrial discharge, agricultural runoff, and urban wastewater. Untreated or inadequately treated effluents from industries, along with sewage flowing in from urban settlements, significantly degrade its water quality.

Shivam Gupta, a Delhi-based policy researcher, points to multiple upstream factors. “The industrial belts of Panipat and Sonipat (in Haryana) are significant contributors,” he says.

“There are several industries located roughly 80 kilometres upstream of the Wazirabad barrage. Wastewater from these areas often enters the river with inadequate treatment.”

In fact, in January 2025, the National Green Tribunal (NGT) had asked the Haryana government to submit an action plan after a court-appointed committee found that 83 percent of industrial units in Sonipat were discharging effluents without adequate treatment, contributing to pollution in the Yamuna.

Similarly, according to a study published by researchers at CEEW in March 2025, Panipat, located around 85 km upstream and known for its textile and dyeing industries, too, releases a toxic mix of untreated chemicals into the Yamuna, severely deteriorating its water quality.

The Delhi High Court has, on multiple occasions, taken suo motu cognisance and pulled up the Delhi Jal Board for inaction on the issue.

In June 2025, the court directed the Delhi Jal Board, the Municipal Corporation of Delhi (MCD), the Delhi State Industrial and Infrastructure Development Corporation, and the Delhi Pollution Control Committee to coordinate efforts to prevent untreated sewage from entering the Yamuna.

Despite repeated court directives requiring states that draw from or discharge into the Yamuna to ensure adequate freshwater flow, compliance has remained poor.

There's also a reason why high ammonia levels in the Yamuna typically spike during the late-winter period, even though the volume of pollutants discharged does not significantly change.

“During winters, the river’s flow is low, which reduces its natural dilution and assimilation capacity. As a result, pollutant concentrations—including ammonia—rise. The river may be receiving roughly the same volume of sewage and industrial wastewater, but because there is less water in the system, the concentration becomes much higher,” explains Bassi.

In contrast, ammonia levels tend to decline during the monsoon and post-monsoon months, when increased river flow improves dilution.

Not Just a Delhi Problem

High ammonia levels are not confined to Delhi’s stretch of the Yamuna. The problem also extends beyond a single river basin. Rivers across India are reporting increasing ammonia concentrations.

The Central Pollution Control Board (CPCB) tracks Ammonia as N (NH3-N), under its National Water Quality Monitoring Programme (NWMP), where it is included among the key chemical parameters measured at surface water stations nationwide. However, the latest dataset currently available on the NWMP portal dates back to 2023.

More recent insights appear in the 2025 Report on Water Quality Hotspots in Rivers of India. Using CPCB monitoring data from 2023 and 2024, the report flags widespread ammonia contamination across multiple river systems.

In 2023, Ammonia levels crossed the 1.2 mg/L threshold at 42 monitoring stations spanning 20 rivers, including the Yamuna, Agra Canal, Arpa, Bhima, Brahmani, Dhadhar, Hindon, Kanhan, Sabarmati and Wardha.

The pattern persisted in 2024, when 47 stations across 22 rivers—among them the Ganga, Betwa, Damodar, Kali, Shipra, Sabarmati and the Yamuna—recorded concentrations above the same benchmark.

A year-on-year review of identified hotspots points to 66 notable seasonal trends across pre-monsoon, monsoon and post-monsoon periods, indicating that while ammonia levels fluctuate through the year, the contamination remains both widespread and recurring.

Need Better Monitoring, More Robust Data, and Updated Machinery

“When these existing raw water treatment plants were designed, they were designed considering various pollutant levels that we used to receive in the Yamuna. Major plants like the Wazirabad and Chandrawal plants have been functioning for decades,” explains Bassi.

“Over the years, particularly in the last 5 to 6 years, there has been a spike in the concentration of most of the pollutants in the raw water. Because of increasing industrial and agricultural activity, it is becoming more concentrated in the upstream part from where the water is entering into Delhi.,” he adds.

Experts The Quint spoke to also note that the treatment technology in use has not kept pace with this shift and is now outdated for current pollution loads, adding that relying on stopgap measures—such as waiting for water levels to rise and dilute contaminants—will only lead to repeated supply disruptions.

They say newer technological interventions, including pre-chlorination and ion-exchange techniques that can break down ammonia, can be explored. “Once these technologies are in place, water supply can continue uninterrupted without high ammonia concentrations,” they explain.

With a population exceeding 2.5 crore, Delhi requires around 1,250 million gallons per day of water. Currently, 10 treatment plants supply 990-1,000 million gallons per day, with only marginal capacity additions in recent years, even as demand continues to rise. To address this gap, the Delhi Jal Board has planned three new water treatment plants at Iradat Nagar (near Narela), Chhatarpur, and Najafgarh, which will collectively add 235 million gallons per day to the system.