Do we realize what Nitrogen is doing around us?

The same nitrogen helping produce our food is also linked to groundwater pollution, blue baby syndrome, algae bloom, acid rain, photochemical smog, and even climate change?

An element essential for life is also becoming a source of environmental stress when its natural balance is disturbed.

Nitrogen is indispensable for agriculture. It is essential for chlorophyll synthesis, vegetative growth, amino acid formation, and protein synthesis in plants. Because nitrogen is a structural component of chlorophyll molecules, it directly influences photosynthesis and leaf greenness. But plants do not need nitrogen alone. They also require phosphorus, potassium, sulphur, and several micronutrients in balanced proportion. The challenge begins when one nutrient is supplied excessively while others are ignored.

Much of the nitrogen entering our food system comes through urea CO(NH₂)₂, one of the most widely used fertilizers in modern agriculture. Yet plants cannot directly absorb atmospheric nitrogen N₂, even though it makes up nearly 78% of the air, because this form is chemically very stable.

Nature solves this through biological nitrogen fixation. Soil bacteria such as Rhizobium, Azotobacter, Azospirillum, Frankia, Nostoc and Anabaena convert atmospheric nitrogen into forms plants can use. Lightning also helps fix nitrogen naturally. But these natural processes are slow, which is why chemical fertilizers became central to modern agriculture.

This creates two forms of nitrogen: productive nitrogen and runaway nitrogen.

Productive nitrogen is absorbed by plants and supports food production. Runaway nitrogen escapes into soil, water, and air, where it becomes pollution.

In India, nitrogen fertilizer is highly subsidized, especially urea. Because it is cheap and easily available, it is often applied beyond requirement, while phosphorus, potassium, sulphur, and micronutrients may not be supplied adequately. The result is nutrient imbalance, declining soil health, and inefficient fertilizer use.

This is why agriculture must move toward balanced fertilization: right nutrient, right amount, right proportion.

Highly subsidized fertilizers also create the risk of diversion and black marketing. That is why Neem-coated urea is important. Neem coating slows nitrogen release into soil and improves nitrogen-use efficiency. Sulphur-coated urea offers additional benefit because sulphur itself is essential for enzyme activity and protein synthesis in plants.

When urea enters soil, it converts into ammonium NH₄⁺, and then nitrification begins:

NH₄⁺ → NO₂⁻ → NO₃⁻

Ammonium first becomes nitrite and then nitrate.

Nitrate NO₃⁻ easily leaches into groundwater, creating invisible pollution. This nitrate contamination is linked to Methemoglobinemia(Blue baby syndrome), where infants lose blood oxygen-carrying capacity because nitrate interferes with normal oxygen transport.

When excess nitrogen enters lakes and ponds, it causes Eutrophication, resulting in algae bloom, oxygen depletion, and stress on aquatic ecosystems.

Nitrogen also enters the atmosphere in the form of Nitrous oxide during nitrification and denitrification. In flooded rice fields, anaerobic conditions intensify denitrification.

Nitrous oxide is about 295 times more potent than carbon dioxide (CO₂) over a 100-year period in terms of global warming potential, which means even small emissions can significantly intensify climate change.

Nitrogen oxides NO and NO₂ also react under sunlight and form Photochemical smog.

In sunny urban air, NOₓ + VOCs + strong sunlight produce ozone, PAN (Peroxyacetyl Nitrate) and other secondary oxidants.

Stratospheric ozone protects life, but ground-level ozone harms lungs, crops, and ecosystems.

Nitrogen oxides also react with water:

4NO₂ + 2H₂O + O₂ → 4HNO₃

This forms nitric acid, contributing to Acid rain.

At the same time, atmospheric ammonia NH₃ from fertilizers and livestock reacts with sulfuric acid:

2NH₃ + H₂SO₄ → (NH₄)₂SO₄

Ammonia does not directly create acid rain, but it forms ammonium sulfate particles that contribute to PM2.5 pollution.

Recognizing this, the European Union introduced the Nitrates Directive to reduce nitrate pollution from agriculture.

The story does not end in agriculture.

Coal extends the same chain of environmental imbalance.

In Hasdeo Arand, nearly 1.7 lakh contiguous sal and teak trees have been cut for coal mining. These forests acted as natural carbon sinks. Their removal means less carbon sequestration and more atmospheric carbon dioxide.

Coal contains carbon along with trace elements such as mercury, cadmium, nickel, arsenic, and lead.

When coal burns, CO₂, SO₂ and NOₓ are released. Nitrogen oxides here form because nitrogen present in coal and atmospheric nitrogen react at high temperatures during combustion.

Sulfur dioxide and nitrogen oxides combine with atmospheric moisture to produce acid rain, which changes soil pH and damages nutrients.

Coal combustion also produces Carbon monoxide when burning is incomplete.

Carbon monoxide binds with hemoglobin 200–250 times more strongly than oxygen, forming carboxyhemoglobin and preventing oxygen transport to vital organs.

Coal ash left after combustion contains arsenic, lead, and mercury.

India’s coal has high ash content, making it poor-quality fuel. That is why the steel sector imports nearly 95% of coking coal, because steel production requires ash content ideally below 12%.

Urban ecology shows similar imbalance.

In Singrauli, arsenic presence in surface water has raised concerns because arsenic exposure can cause skin cancer, bladder cancer, lung cancer, and nerve damage.

In Mumbai, nearly 70% of wetlands and mangroves have been destroyed, weakening natural flood absorption systems and increasing flood vulnerability.

The pattern is clear:

Excess nitrogen pollutes groundwater.

Coal releases sulfur, nitrogen oxides, and toxic gases.

Forests are cleared for mining.

Wetlands disappear in cities.

Soil loses nutrients.

Water becomes contaminated.

Air becomes toxic.

Climate warming intensifies.

The same nitrogen that feeds us can also warm the planet, pollute water, damage air quality, and silently enter our lives through food, water, and air.

The problem is not nitrogen.

The problem is imbalance.