Decadal Study Reveals Real Causes of Delhi’s Air Pollution Crisis (2014–2024)

Over the last decade, Delhi’s air has transformed from breathable to toxic. Every winter, the city’s skyline disappears under a grey haze, and the Air Quality Index (AQI) shoots to hazardous levels. This crisis is not a sudden phenomenon—it’s a product of years of unchecked emissions, rapid urbanisation, and policy shortfalls. A recent study conducted by Prachi Tewari and Dr. Shweta Jindal from Indira Gandhi Delhi Technical University for Women examines Delhi’s air pollution trends from 2014 to 2024, providing an in-depth look at how multiple factors have combined to create one of the world’s most persistent urban air quality disasters.

The findings reveal that while stubble burning has long been blamed, its contribution has sharply declined. Meanwhile, vehicular emissions, industrial activity, and population growth have emerged as dominant forces driving Delhi’s pollution. Despite various mitigation efforts—ranging from electric vehicle adoption to dust control—Delhi’s AQI levels remain dangerously high, averaging 374 in November 2024.

Understanding Delhi’s Pollution Landscape

Air pollution refers to the contamination of the atmosphere by harmful substances such as particulate matter (PM2.5 and PM10), carbon monoxide (CO), ozone (O₃), and nitrogen oxides (NOx). According to the World Health Organization (WHO), Delhi’s air quality has exceeded safe limits by more than 35 times, ranking it among the most polluted cities globally.

The human cost of this pollution is severe—millions of Delhi’s children have missed school days due to health emergencies, while cases of asthma, chronic bronchitis, and heart disease have sharply risen. The city’s geography, wedged between Haryana and Uttar Pradesh, coupled with its weather extremes—scorching summers, heavy monsoons, and stagnant winters—worsens its pollution dynamics.

The Shifting Blame: Beyond Stubble Burning

For years, stubble burning in neighbouring states like Punjab and Haryana has been the main scapegoat for Delhi’s pollution. However, the study found a remarkable decline in stubble burning incidents between 2021 and 2024—from 71,304 cases in Punjab in 2021 to just 9,655 in 2024. Haryana also reported a similar drop. This progress was the result of large-scale government initiatives like distributing machinery for in-situ residue management and financial aid under the Crop Residue Management Scheme, amounting to over ₹3,300 crores.

Despite this, air quality improvement remained negligible. This discrepancy indicates that other persistent sources—particularly vehicular and industrial emissions—play a far greater role today than previously acknowledged.

Vehicular Emissions: The Dominant Polluter

Delhi’s roads are home to over 7.6 million private vehicles and more than 3 lakh public vehicles, making transport the single largest contributor to the city’s air pollution. According to the Centre for Science and Environment (CSE), vehicular emissions accounted for 51.5% of Delhi’s pollution in late 2024—far surpassing stubble burning, which contributed just 8.19%.

While initiatives like CNG adoption, the Odd-Even traffic rule, and promotion of electric vehicles (EVs) have been rolled out, their impact has been modest. The number of registered EVs in Delhi has grown exponentially since 2019, yet internal combustion vehicles continue to dominate, largely due to affordability and infrastructure challenges.

Industrial Growth and Power Sector Emissions

The industrial expansion of Delhi has been another silent contributor. Between 2011 and 2022, the number of working factories in Delhi rose from 8,219 to 8,690, with industries like textiles, basic metals, and machinery leading the way. In 2014 alone, Delhi’s total greenhouse gas emissions were recorded at 37.91 million tonnes of CO₂ equivalent, with power plants contributing 43% and vehicles 32%.

Even as renewable energy generation increased from 53.06 BU in 2013-14 to 203.55 BU in 2022-23, total emissions have continued to rise. This suggests that while Delhi’s energy systems are cleaner per unit, overall industrial and residential demand continues to outpace sustainability measures.

Population Growth and Urban Pressure

Delhi’s population grew from 25 million in 2014 to nearly 34 million in 2024, expanding at a rate of 2.63% annually. This explosion in population has led to higher energy consumption, waste generation, and construction—all of which feed into rising pollution. Interestingly, the study found a weak correlation between population growth and AQI, suggesting that while population density amplifies emissions indirectly, pollution stems more from poor infrastructure and inefficient systems than sheer numbers.

Policy and Mitigation Efforts: What’s Working, What’s Not

Delhi has implemented multiple pollution control strategies over the decade. The Graded Response Action Plan (GRAP) is among the most prominent, triggering stricter restrictions as AQI worsens—from dust control measures and DG-set bans at mild stages to complete construction halts and traffic restrictions under severe conditions.

Industrial mitigation policies have pushed over 1,700 industries to adopt PNG fuel, while waste burning and diesel generator bans are enforced by the Delhi Pollution Control Committee (DPCC). The Delhi Metro, now a UN-certified carbon-credit project, has also played a pivotal role in reducing vehicle dependency, carrying nearly 5 million passengers daily pre-pandemic.

However, despite these interventions, Delhi’s AQI remains trapped between the “poor” and “severe” categories for most of the year. The study concludes that piecemeal policies and short-term bans have failed to deliver lasting change.

Delhi’s air pollution crisis is not just an environmental problem—it’s a public health emergency. The data show that while stubble burning has declined, vehicular and industrial emissions continue to dominate, undoing the benefits of partial progress in other areas. Citizens are paying the price in the form of chronic illness, lost productivity, and deteriorating quality of life.

The study underscores a critical point: Delhi doesn’t need adaptation—it needs transformation. Cleaner transport systems, stricter enforcement, sustainable industrial practices, and long-term urban planning are the only viable pathways to reclaim breathable air. For the millions who call Delhi home, clean air must no longer be a seasonal wish—it must become a right.