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On a hot afternoon in Dichaon village on the outskirts of Delhi, one can see lush green rows of cauliflower and jowar (sorghum) from a distance. But as you move closer, a strong stench hangs heavily in the air.
Just 500 metres from the green expanse is a drain choked with untreated wastewater and solid waste. What is not visible though is that through an underground pipe, the same polluted water is irrigating the fields, feeding the crops that are almost ready to be harvested and sold.
A few metres away from the fields, a worker, Mitthu (he only uses his first name) is preparing his afternoon meal inside a small shed built at the end of the cultivated land.
When asked about the source of water used for irrigation, Mitthu points towards the channel.
“Yes, we use drain water for irrigation here,” he said.
But what about the water needed for drinking and cooking purposes? For that, Mitthu said they rely on groundwater.
The workers here told Down To Earth (DTE) that the water from the drain is widely used for irrigating the crops, which are consumed by both humans and animals.
When asked whether he consumed the vegetables grown there, Mitthu replied, “Hum nahi khaatey, gobhi acchi nahi lagti” (“I do not eat it, I don’t like cauliflower").
Delhi’s south-west district of Najafgarh is one of the national capital’s prominent agricultural belts where wastewater irrigation continues in several villages.
A study titled Assessment of Drain Water Used for Irrigation in the Delhi Region 2020 noted that “severe water stress” has pushed farmers towards alternatives such as wastewater for irrigation purposes. Researchers have also observed that wastewater remains year-round and is an easily accessible irrigation source in several agricultural belts surrounding Delhi.
The drain that feeds these fields is among the most polluted and voluminous in the capital.
According to a study titled Hydrogeological characterization and assessment of groundwater quality in shallow aquifers in vicinity of Najafgarh drain of NCT Delhi 2013, the Najafgarh drain is the biggest drain in Delhi and contributes about 60 per cent of the total wastewater that gets discharged from Delhi. The drain enters Delhi from Haryana in the capital’s south-west corner. It traverses a length of 51 km before joining the Yamuna river. It carries flood water, wastewater from Haryana and surface runoff from the adjoining catchment. There is considerable contamination of groundwater by industrial and domestic effluents.
The dependence on wastewater irrigation despite concerns over contamination remains widespread across Delhi’s peri-urban farming belt. In several villages surrounding the capital, polluted drain water continues to be used for cultivation.
Workers move through the fields, tending crops that eventually reach Delhi’s kitchens through Azadpur Mandi, one of Asia’s largest wholesale vegetable markets and consumers have almost no way of identifying whether vegetables sold in markets have been grown using treated water, groundwater or untreated wastewater.
This practice persists despite years of warnings from environmental researchers, government agencies, and judicial bodies over the possible health and environmental risks linked to wastewater-fed agriculture.
According to a report by DTE, despite treating 72 per cent of its generated sewage, Delhi generates about 3,600 million litres per day.
In several peri-urban farming belts surrounding the capital, this wastewater becomes an irrigation source, particularly where freshwater access remains limited.
From a short distance where Mitthu is working, another group of farmers are cultivating ladyfinger and beans. They denied using drain water.
“We use fertilisers and tubewell water only,” one farmer claimed, insisting that wastewater was not being used for irrigation in their fields.
“The workers on the fields around naala number 9 use only drain water for agricultural practices,” he added.
He is talking about Hiran Kudna, a village near naala number 9, where farmers spoke about their dependence on wastewater.
When asked whether prolonged exposure to such water had caused health problems among farmers or residents, he dismissed the concern.
“Abhi tak to kisi ki tabiyat kharab nahi hui, aas-paas sab hi yahi khaate hain,” (“Till now, nobody has fallen sick; everyone around here eats this.”)he said.
Like most families in the area, he added, they consume the vegetables grown on these fields themselves.
A conversation with women in the nearby field reflected uncertainty. When asked whether they were aware of chemicals possibly present in the drain water, some responded hesitantly.
“Haan, ho sakta hai,” (“Yes, it is possible.”) one woman said softly, before directing further questions to the male members of the household.
Another farmer in the same field defended the use of wastewater altogether.
He argued that drain water contains “requisite chemicals” beneficial for crop growth and viewed it as useful for cultivation.
Unlike packaged food products, fresh vegetables sold in mandis (wholesale markets) and roadside markets carry no traceability system informing buyers about cultivation conditions or irrigation sources.
“Sabziyon ke swaad se antar pata chal jaata hai. Tubewell ke paani se ugayi gayi sabziyaan meethi hoti hain, aur naale ke paani wali sabziyon ki smell alag hoti hai,” (“You can tell the difference from the taste of the vegetables. Vegetables grown using tubewell water taste sweeter, while those irrigated with drain water have a different smell.”) said a farmer in Dichaon village who uses groundwater.
In 2015, the National Green Tribunal (NGT) prohibited vegetable cultivation on parts of the Yamuna floodplains, warning that crops irrigated with polluted water could pose serious health risks. Multiple studies by institutions such as The Energy and Resources Institute (TERI), National Environmental Engineering Research Institute (NEERI) and Delhi government agencies have since documented contamination concerns linked to wastewater-fed agriculture.
Environmental researchers have repeatedly warned that long-term irrigation using untreated wastewater may lead to the accumulation of heavy metals and contaminants in agricultural soil and crops, potentially affecting both ecosystems and human health over time.’
Yet on the ground in villages surrounding Najafgarh, drain water continues to irrigate crops consumed across the capital.
