India’s agricultural transformation has long been driven by technological shifts—from the Green Revolution’s high-yielding varieties to the widespread use of synthetic fertilisers. Today, nano urea is being positioned as the next leap: a precision input that promises higher efficiency, lower environmental damage, and reduced dependence on conventional fertilisers. Backed by policy support and fast-tracked approvals, its rollout has been rapid and ambitious .
Yet a critical question remains insufficiently examined: are we scaling nano urea faster than we are understanding its long-term implications for public health and environmental safety?
Efficiency gains, limited lens
The appeal is clear. Nano urea, typically in the 20–50 nanometre range, is designed for foliar application, enabling more efficient nitrogen uptake. Studies suggest nitrogen-use efficiency could rise to nearly 70%, compared to 30–35% for conventional urea. Field trials report modest yield gains—around 3–9%—and indicate that conventional urea use could fall by up to 25% .
In a country grappling with nitrogen overuse, groundwater contamination, and rising fertiliser subsidies, these gains matter. But efficiency alone does not make a technology risk-free. Agricultural inputs operate within complex ecological and biological systems where unintended consequences often emerge slowly .
When size changes behaviour
What sets nano urea apart is not just its formulation, but its scale. At the nanoscale, materials behave differently. Their small size and high surface reactivity allow them to cross biological barriers, interact with cellular systems, and potentially accumulate within tissues .
Nanotoxicology research shows that engineered nanoparticles (1–100 nm) can enter systemic circulation and get deposited in organs such as the liver, lungs, kidneys, and brain, where persistence may trigger chronic toxicity. Their reactivity promotes the generation of reactive oxygen species, leading to oxidative stress, inflammation, DNA damage, and apoptosis—pathways linked to carcinogenic and neurodegenerative outcomes, including conditions such as Alzheimer’s and Parkinson’s disease .
Crucially, toxicity rises as particle size falls. Reducing size from about 30 nm to 3 nm can increase reactive surface atoms from roughly 10% to nearly 50%, amplifying biological interactions. Complementary studies associate chronic nanoparticle exposure with respiratory dysfunction, cardiovascular stress, and immune dysregulation .
Pathways we barely track
The risks extend beyond direct exposure. Spray drift and runoff can introduce nano urea into soil and water systems. While conventional urea hydrolyses into ammonium and nitrate, the fate of nanoparticle carriers or stabilising agents remains unclear .
Even more uncertain is dietary exposure. Do nanoparticles persist in plant tissues? Can they enter the food chain? India currently lacks systematic mechanisms to monitor such pathways or assess cumulative exposure risks .
Early warnings, familiar patterns
In the absence of long-term epidemiological data, related evidence offers cautionary signals. In the case of nano-liquid urea, forensic evidence has already documented acute toxicity following ingestion, including severe metabolic disturbances and uremic complications. Moreover, urea itself can destabilise proteins and nucleic acids; its nano-formulation may enhance cellular uptake, potentially intensifying these effects .
The risks associated with new materials often become evident only after widespread, long-term exposure. India’s past experiences—including the health impacts of DDT and Endosulfan, the Bhopal Gas Disaster, chronic arsenic and fluoride contamination, mercury pollution in Kodaikanal, toxic exposure from informal e-waste recycling, and stubble burning—underscore a recurring pattern of delayed regulation and substantial long-term public health costs .
Regulation still catching up
The government has begun to respond. The 2026 amendment to the Fertiliser Control Order introduces stricter requirements for biosafety testing, product approvals, and safety labelling. However, these remain largely focused on pre-market evaluation .
What is missing is robust post-market surveillance—tracking real-world exposure, monitoring environmental residues, and studying long-term health outcomes. Globally, regulatory frameworks are more cautious. The European Union and the United States emphasise case-by-case risk assessment of nanomaterials, with a strong focus on long-term safety and environmental behaviour .
Compounding these gaps is a disconnect between scientific evidence and public messaging. Claims that nano urea can fully replace conventional fertilisers have been questioned by independent researchers as lacking robust empirical support. In a sector where farmer trust is critical, such exaggerated claims risk undermining both scientific credibility and policy outcomes .
The way forward
India does not need to abandon nano urea. But it must adopt a more precautionary, evidence-based approach. This includes strengthening long-term health surveillance, expanding environmental monitoring, ensuring independent validation of safety claims, and investing in farmer awareness .
Nano urea may well play a role in India’s agricultural future. But before it becomes ubiquitous, the country must fully understand not only its benefits, but also its risks. Because in public health, what remains invisible today often becomes undeniable tomorrow .
