What are the Leading Causes of Air Pollution in Delhi?

Delhi tops the chart amongst the Indian cities with the worst levels of air pollution. During winters, the city gets enveloped by the dense layer of smog that results in IMA’s declaration of a public health emergency.

The alarming levels of particulate matter concentrations in the air cause devastating health, economic, and environmental impacts in the city. It pushes the city into the health crisis and incurred high costs by disrupting normal life out of gear.

This dire state of affairs caused by extreme air pollution with high toxins levels in the city’s air is further compounded by seasonal emissions from forest fires and dust storms. It leaves millions of people vulnerable to respiratory disorders for long periods.

Reasons for the rise of air pollution in India

Let’s look at the leading reasons for the exponential rise of air pollution in India.

Crop/Stubble Burning

Delhi shares its geographical borders with Haryana, Uttar Pradesh, and Rajasthan. The crop or stubble burning in these states is one of the primary causes of air pollution in the national capital.

The states of Punjab and Haryana are leading producers of rice and wheat crops. The leftover rice stalks and straws after harvest are burned as a measure of clearing the outfields.

This stubble burning occurs during the beginning of the new harvest season, contributing to the dense layer of smog over Delhi’s sky in winters.

This burning is often accompanied by meteorological conditions like slow wind speeds and lower temperatures that trap the air’s smoke. Thus, stubble burning drastically deteriorates the air quality in the capital city.

Vehicular Emissions

With 28 per cent of all PM2.5 emissions, vehicular emissions are the leading contributors to PM2.5 emissions in Delhi. These vehicles are responsible for up to 80% of harmful gases like nitrogen oxides and carbon monoxide in the city’s atmosphere.

As per the study on Delhi’s pollution, vehicles are responsible for up to 41 per cent of the total air pollution in the capital. The vehicular emissions from millions of the two-wheelers and four-wheelers have pushed the air quality index to severe levels.

The National Environmental Engineering Research Institute (NEERI) and the Central Pollution Control Board (CPCB) have acknowledged vehicular emission as the leading cause of Delhi’s extreme air pollution.

Industrial Pollution

Delhi boasts of the highest cluster of (SSI) small-scale industries in the country.

Most of these industries are highly pollutive and don’t meet the emission limitations set by the central pollution control board (CPCB) on water, soil, and air emissions.

Delhi is home to some of the most polluted industrial clusters in India.

As per the study, the industrial pollution caused by over 3000 industries located across the Delhi-NCR area contributes to 18.6 % of the total poor air quality index in the capital.

The rampant usage of cheaper fossil fuel-based alternatives by industries to avoid carbon tax levy also contributes to industrial pollution. This industrial pollution and garbage dump also add to the smog building in the air.


The high levels of the pollutants emitted at the construction sites contribute significantly to air pollution. There are approx 350 plus brick kilns at the outskirts of Delhi.

During winters, the brick kilns’ emissions increase because the winds are relatively slow, and gases and particulate matter stay suspended in the air for longer at one place. This fine dust from the various construction activities adds to the smog.

As per DPCC officials, construction sites cause up to 30 per cent of air pollution due to the dust in the capital. The large-scale construction of the various infrastructure projects in the region renders the air quality poorer, especially during winters.


Delhi is one of the most crowded and over-populated cities in the country. This contributes to the increased air pollution due to increased vehicular emissions, increased combustion of fuel for heating, cooking, etc.

Residents have started to install air purifiers in their living room and bedroom to combat this issue. Air purifiers provide some relief as it filters out all the harmful particles in the air.


The severity of air pollution in Delhi affects millions of people every year, especially during the winters. All the reasons mentioned above combine to make the air quality index the worst in the country.

Whether it’s about vehicular emissions, suspended dust due to construction activities, industrial pollution due to heavy industry or brick kilns, stubble burning, or combustion of fuels, the comprehensive approach to effectively address every reason is needed.


Preksha is passionate about writing articles that will inspire readers to make better choices. You will find her eating desserts for lunch, dinner and any time of the day. Also, she is the chief playlist engineer for any road trip.

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