Delhi's Air Pollution: A Deadly Crisis

Delhi, India's capital, has been ranked the most polluted capital city in the world for the sixth year in a row. The city's air quality is worse than India's overall air quality, with a PM2.5 reading of 92.7 micrograms per cubic metre. This is more than 10 times the World Health Organization's annual PM2.5 guideline value. The poor air quality in Delhi is caused by various factors, including industrial and vehicular emissions, crop burning by farmers in nearby states, and the burning of coal for energy generation. The pollution has severe health impacts, reducing life expectancy in India by an estimated 5.2 years and causing severe neurological, cardiovascular, and respiratory diseases, lung capacity loss, and cancer.

Vehicular emissions

Delhi's air quality is often described as "very poor" and "severe", with the city being ranked as the world's most polluted capital city. Vehicular emissions are a significant contributor to this issue.

Vehicles in Delhi contribute more to air pollution than stubble burning in neighbouring states. Slow incremental changes in the public transport system, a lack of integration, inefficient last-mile connectivity, and hidden subsidies for personal vehicles have been identified as factors contributing to the city's mobility crisis.

Local transport, including two- and three-wheelers, as well as heavy-duty vehicles, contribute significantly to the evening PM2.5 levels in Delhi, with a share of 18%. Two- and three-wheelers account for 50% of this contribution, while heavy-duty vehicles account for 30%. The combined contribution of passenger cars, light-duty vehicles, and resuspended road dust to the daily mean PM2.5 is relatively smaller, at 20%.

During periods of unfavourable meteorological conditions, vehicular emissions can account for 38-40% of Delhi's air pollution, with secondary inorganic aerosols contributing 30-35%. Calm winds and low temperatures allow for the accumulation of pollutants, exacerbating the situation.

The impact of vehicular emissions on Delhi's air quality is particularly noticeable during the winter months. The combination of emissions from vehicles, industrial activities, crop burning in nearby states, low wind speeds, and the bursting of firecrackers during festivals results in hazardous air quality levels.

Industrial emissions

Delhi, India's capital territory, has been ranked as the world's most polluted capital city. With a population of over 30 million, Delhi has consistently maintained high pollution levels, with an annual average of 91.6 μg/m³, far above the World Health Organization's annual PM2.5 guideline value of 5 μg/m³.

The effects of industrial emissions on air quality are not limited to Delhi but extend across India. In 2024, India was ranked as the third most polluted country globally, with 11 of the top 20 most air-polluted cities worldwide located within its borders. The country's average PM2.5 level, a measure of fine particulate matter that can cause respiratory issues and other health problems, was recorded at 54.4 micrograms per cubic metre, significantly higher than the safe limit of 12 to 15 micrograms per cubic metre.

The impact of industrial emissions on air quality is a global concern, and various countries are grappling with the challenge of reducing industrial pollution. In the United States, for example, the Environmental Protection Agency (EPA) has faced criticism for its handling of toxic air pollutants emitted by chemical plants and industrial facilities. While the EPA's regulations aim to protect public health, business groups have argued that the requirements are burdensome and costly. The recent overturning of an EPA rule limiting hazardous air pollutants highlights the ongoing tension between public health and industrial interests in addressing air pollution.

To effectively tackle industrial emissions in Delhi and improve air quality, a multi-faceted approach is necessary. This includes stricter enforcement of environmental regulations, incentivising the adoption of cleaner technologies, and providing support for industries to implement pollution-control measures. Additionally, collaboration between governments, industries, and environmental organisations is vital to develop long-term solutions that balance economic development with the need to protect the health and well-being of Delhi's residents.

Crop burning

Delhi, India's capital, has been dubbed a "medical emergency" due to its poor air quality. The city's air quality is a year-round issue, but it is at its worst from mid-October through mid-December. One of the factors contributing to this is the burning of crop remains by farmers in nearby states.

Crop residue burning is a common practice in Indian agriculture, particularly in the northwest region, where there is a tight schedule for the harvest-to-sowing transition under the predominant rice-wheat rotation cropping system. Burning crop residues allow for the cheap and fast disposal of crop residues, making it a cost-effective solution for small and medium farmers. However, this practice has severe negative impacts on air quality in cities like Delhi.

NASA's Aqua satellite detected a 60% increase in the number of agricultural fires between 2002 and 2016, indicating the growing severity of the issue. The burning of crop residues releases fine particulate matter (PM2.5) into the atmosphere, which can clog lungs and cause a host of diseases, including severe neurological, cardiovascular, and respiratory issues, lung capacity loss, and even cancer.

The dispersion and transport of fire emissions from agricultural fires can impact air quality over a large area, and Delhi is a major recipient of pollution from these fires. The combination of seasonally slower winds and smoke emitted from coal-fired power plants in the region further exacerbates the problem, leading to a drastic spike in pollution levels during the winter months.

While crop residue burning is not the only factor contributing to Delhi's poor air quality, it is a significant one. The Indian government and organisations like The Nature Conservancy are working to address this issue by helping farmers adopt alternative practices and providing resources to extinguish agricultural fires. These efforts aim to reduce air pollution and improve the health of both the soil and the people of Delhi.

Poor industrial regulation

Delhi, India's capital, has been dubbed the "world's most polluted capital" for the sixth year running. The city's poor air quality is attributed to various factors, one of which is poor industrial regulation.

Delhi's industrial areas, particularly West Delhi, suffer from poor infrastructure, cumbersome government policies, and a lack of effective pollution control measures. The high cost of infrastructure is a significant challenge, with civic authorities failing to maintain roads and other basic services despite collecting high property taxes. The road network in West Delhi Industrial Area is disorganized, and the area often experiences flooding, creating a breeding ground for severe epidemics.

The privatization of the power distribution system has brought some improvements, but more needs to be done to regulate Discoms. The Delhi Electricity Regulatory Commission (DERC) has been urged to act as a watchdog and bring more transparency to the sector.

Land availability is also an issue, with high rents and circle rates impeding the growth of industries in West Delhi. Small-scale industrial units struggle to find affordable land, and the complex government procedures for various approvals hinder rather than support industrial development.

The water supply infrastructure is another concern, with broken pipelines leading to seepage and, at times, sewer water mixing with the main supply. Industries in West Delhi suffer losses due to drainage water and overflowing sewage flooding their premises.

The poor industrial regulation in Delhi contributes to the city's air pollution crisis, with factories and industries emitting fumes and failing to implement adequate pollution-control measures.

Weak enforcement of environmental laws

Delhi's air pollution has been a major environmental and health concern, with the city frequently ranked among the world's most polluted cities. The poor air quality in Delhi is caused by a combination of vehicle emissions, industrial pollution, stubble burning from neighbouring states, and dust from construction activities. The Air Quality Index (AQI) in Delhi often ranges from "poor" to "severe," particularly during the winter months.

One of the critical factors contributing to Delhi's air pollution is the weak enforcement of environmental laws. India's rapid industrialization and development in recent decades have not been adequately regulated, resulting in factories failing to implement effective pollution control measures. The country's environmental laws are not stringently enforced, allowing industrial activities to continue emitting harmful pollutants into the atmosphere without consequence.

The Indian government has faced criticism for its inadequate response to the air pollution crisis. While short-term measures, such as sprinkling water and temporarily restricting vehicle entry into cities, are sometimes implemented, they only provide temporary relief without addressing the underlying causes of the problem. The government's efforts fall short of what is needed to effectively tackle the complex and interrelated factors contributing to Delhi's poor air quality.

The lack of stringent enforcement of environmental laws has far-reaching consequences for public health. Air pollution in Delhi leads to severe respiratory diseases, cardiovascular issues, lung capacity loss, and even cancer. It is estimated that air pollution causes approximately 2 million deaths per year in India, with northern India expected to lose an average of 7.6 years of life expectancy due to poor air quality.

To address the weak enforcement of environmental laws, there have been growing calls for stricter regulations and their effective implementation. The public's awareness of air pollution as a critical issue is increasing, with 85% of Delhi's residents supporting stricter air quality laws and enforcement. The Indian government has also launched initiatives like the National Clean Air Program, aiming to reduce particulate matter pollution by 30% by 2024. However, the success of these programs depends on strong enforcement and a commitment to tackling the root causes of air pollution in Delhi.

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