Ethiopian Volcanic Ash Over India: Why Delhi’s Air Quality Was Spared, But Your Flight Wasn’t 

A massive ash plume from Ethiopia’s Hayli Gubbi volcanic eruption, its first in 12,000 years, drifted over northern Indian states this week, sparking immediate concerns that it would exacerbate Delhi’s severe air pollution crisis. However, according to the India Meteorological Department (IMD), the threat never materialized at ground level, as the ash cloud remained confined to the upper troposphere—far above the altitude where weather and breathable air quality are determined. While the plume had a significant impact on aviation, forcing the cancellation and rerouting of numerous international flights due to the severe risk abrasive ash poses to jet engines, experts confirmed it had absolutely no effect on Delhi’s AQI, providing a stark lesson in the layered nature of our atmosphere and distinguishing a high-altitude aviation hazard from a ground-level public health emergency.

Ethiopian Volcanic Ash Over India: Why Delhi’s Air Quality Was Spared, But Your Flight Wasn’t 

A ghost from the Earth’s deep past arrived silently over India this week. From the heart of Ethiopia’s Afar region, the Hayli Gubbi volcano—dormant for nearly 12,000 years—awoke with a fury, spewing a colossal plume of ash and gas high into the atmosphere. Within days, this airborne shroud had traversed the Arabian Sea, casting a pall over the skies of Gujarat, Rajasthan, Punjab, Haryana, and the Delhi-NCR. 

The timing could not have been more provocative. As North India grapples with its annual siege of winter pollution, the news of a volcanic ash cloud triggered an immediate and understandable alarm. Was this a new, exotic ingredient about to compound Delhi’s toxic air quality cocktail? 

The answer, according to the India Meteorological Department (IMD), was a definitive and surprising “no.” The threat, they declared, had “completely exited” Indian skies by Tuesday night. But this event was far from inconsequential. It presented a fascinating case study in atmospheric science, a stark reminder of global interconnectedness, and a lesson in distinguishing between different kinds of aerial threats. 

The Eruption Heard ‘Round the (Aviation) World 

The story begins not over India, but in the geologically hyperactive Afar Triangle of Ethiopia. On Sunday, November 23, 2025, the Hayli Gubbi volcano erupted for the first time since the last Ice Age. This wasn’t just a geological curiosity; it was a powerful event that ejected millions of tons of fine silicate ash and sulphur dioxide gases straight into the upper troposphere and lower stratosphere. 

Propelled by high-altitude jet streams—rivers of air that circle the globe—this plume began a rapid eastward journey. By late Monday night, it had entered Indian airspace. Satellite imagery tracked its progress in real-time, a vast, invisible river of abrasive particles flowing miles above our heads. 

The Anatomy of a Panic: Why We Feared the Worst 

The public concern was instinctive and logical. We are conditioned, especially in North India, to associate hazy skies with dangerous pollution. When we hear “ash cloud,” we think of the grimy residue from a fire, something that must surely settle and smother. The term itself evokes images of cities ground to a halt by falling ash. 

Furthermore, Delhi’s Air Quality Index (AQI) is a constant source of anxiety and news headlines. The idea of a massive external event adding to the locally generated pollution from vehicles, industry, and stubble burning was a terrifying prospect. It felt like an act of nature was about to lock us indoors for reasons beyond our control. 

The Expert Verdict: A Tale of Two Atmospheres 

So, why did this apocalyptic-sounding event leave Delhi’s pollution monitors utterly unfazed? The explanation lies in a critical understanding of our atmosphere’s structure. 

Mrutyunjay Mohapatra, Director General of Meteorology at the IMD, provided the crucial clarification: “The impact of this volcanic ash is being seen only in the upper troposphere… It has no impact on air quality and weather.” 

Let’s break down this scientific reality: 

• The High-Flyer Plume: The ash from Hayli Gubbi was injected and remained at altitudes between 35,000 and 45,000 feet. This is the realm of international aviation, far above the part of the atmosphere where we live and breathe—the planetary boundary layer, which extends only about 3,000 feet from the ground. 

• The Insulated Breathable Zone: Our ground-level weather and air quality are dictated by processes within this boundary layer. Smoke, dust, PM2.5, and PM10 particles from local sources get trapped here, especially in winter by temperature inversions that act like a lid on a pot. The volcanic ash, however, was flowing above this lid, completely disconnected from the air we inhale. There was no mechanism for it to descend en masse into our breathing space. 

• A Different Kind of Particle: Even if some ash had miraculously descended, its impact would be different from the complex chemical soup that defines Delhi’s pollution. Volcanic ash is primarily fine rock and mineral particles. While harmful to inhale, it lacks the toxic organic compounds, heavy metals, and nitrates that make urban PM2.5 so insidiously damaging to human health. 

In essence, the crisis was on a different floor of the atmospheric skyscraper, while we were worried about the air in our ground-floor apartment. 

The Real Victim: Global Aviation Grinds to a Halt 

If the people on the ground were spared, the same cannot be said for the machines in the sky. The volcanic ash cloud’s impact on aviation was immediate, severe, and costly. 

Why is volcanic ash a plane’s worst nightmare? 

• Engine Failure: Jet engines operate by sucking in vast quantities of air. Volcanic ash, which is essentially tiny shards of glass and rock, melts inside the engine’s combustion chamber (which is hotter than the melting point of the ash). It then re-solidifies on the cooler turbine blades, causing a loss of thrust and potentially complete engine failure. 

• Abrasive Damage: The ash sandblasts the windshield, making it opaque, and damages critical sensors like pitot tubes, which measure airspeed. 

• System Contamination: It can clog air conditioning and ventilation systems, potentially introducing harmful gases into the cabin. 

The 2010 eruption of Iceland’s Eyjafjallajökull, which led to the largest airspace shutdown since World War II, serves as a grim reminder. The Indian aviation sector, having learned from such global events, took no chances. 

• Air India cancelled 11 international flights to inspect aircraft that may have passed through the affected corridor. 

• Akasa Air grounded its flights to key Middle Eastern destinations like Jeddah, Kuwait, and Abu Dhabi. 

• At Delhi’s Indira Gandhi International Airport, the ripple effect was clear: at least seven international flights were cancelled and a dozen more delayed, leaving passengers stranded and underscoring the vulnerability of our interconnected world. 

A Historical Perspective: When Volcanic Eruptions Do Change the Climate 

The Hayli Gubbi event was a temporary disruption to aviation. However, history shows that truly colossal volcanic eruptions can alter global climate, though not local air quality in the way we might think. 

The key factor is sulphur dioxide (SO2), not ash. 

When a volcano is powerful enough to inject massive amounts of SO2 directly into the stratosphere (even higher than the troposphere), the gas converts into sulphate aerosols. These tiny droplets form a reflective layer that can circle the globe for years, bouncing solar radiation back into space and causing a period of global cooling. 

• The Pinatubo Effect: The 1991 eruption of Mount Pinatubo in the Philippines was so powerful it lowered the average global temperature by about 0.5°C for nearly two years. 

• The Year Without a Summer: The 1815 eruption of Mount Tambora in Indonesia led to the infamous “Year Without a Summer” in 1816, causing crop failures and famines across the Northern Hemisphere. 

The Hayli Gubbi eruption, while significant, was not on this cataclysmic scale. Its SO2 output and injection height were insufficient to trigger any measurable climatic effects, serving instead as a potent reminder of nature’s power without unleashing its full force. 

Conclusion: A Lesson in Atmospheric Layers and Global Links 

The journey of the Ethiopian ash cloud over India was a non-event for Delhi’s air quality, but a significant event for our understanding. It taught us two main lessons: 

• Not All Hazy Skies are Created Equal: The episode forced a public reckoning with the science of atmospheric science. It highlighted the critical difference between high-altitude phenomena and ground-level pollution, a distinction crucial for informed discourse on environmental issues. 

• The World is Smaller Than We Think: An eruption in a remote African geological rift can, within 48 hours, disrupt the travel plans of thousands in India and the Middle East. It is a stark demonstration of our planet’s intricate and fragile connectivity. 

For now, the plume has passed. The flight schedules are normalizing. But the memory of the time an ancient volcano whispered a warning from 12,000 years past, a warning that drifted over our heads without touching us, but shook the very foundations of our global transit system, will linger. The real pollution battle for Delhi remains, as it always has, firmly on the ground.