Cars' Pollution Contribution: Delhi's Transport Crisis

Delhi's poor air quality is a well-known issue, with the city consistently ranking among the most polluted in the world. Vehicular emissions are a significant contributor to this problem, with data showing that transportation accounts for about 50% of local air pollution in Delhi. This is particularly true during the winter months when inversion layers trap pollutants close to the ground. The high levels of nitrogen oxides (NOx) in the city, which account for 81% of NOx pollution, are largely due to the traffic congestion caused by the influx of vehicles. The adverse meteorology of the region, with no sea breeze to disperse pollutants, further exacerbates the issue. While other factors such as crop burning, firecrackers, construction, and industrial pollution play a role, vehicular emissions remain a critical concern that requires year-round efforts and long-term systemic changes to address effectively.

Vehicular emissions are a major cause of Delhi's winter pollution

Delhi, the capital of India, has been facing a severe air pollution problem for many years. The air quality in Delhi continues to be hazardous, with particulate matter (PM2.5) levels reaching dangerous levels. Vehicular emissions are a major contributor to Delhi's winter pollution, and addressing this issue is crucial for improving the city's air quality.

According to data presented by the Centre for Science and Environment (CSE), local pollution sources in Delhi account for 30.34% of the city's air pollution, with transportation contributing 50.1%. This includes emissions from cars, two-wheelers, and commercial vehicles. During peak traffic hours, when average traffic speed drops, nitrogen dioxide (NO2) levels significantly increase, worsening air quality. The traffic influx also intensifies pollution, particularly nitrogen oxides (NOx), which account for 81% of NOx pollution in Delhi.

The impact of vehicular emissions on Delhi's winter pollution is exacerbated by the city's geographical location and meteorological conditions. Delhi is landlocked and does not benefit from sea breezes that could help disperse pollutants. Additionally, during winter, inversion layers trap pollutants close to the ground, further deteriorating air quality. The combination of high vehicle emissions and unfavourable meteorology creates a deadly mix, leading to severe pollution levels in the city.

To tackle Delhi's winter pollution, a comprehensive approach is necessary. Reducing vehicular emissions is crucial, and this can be achieved by improving public transportation systems, promoting walking and cycling infrastructure, and implementing effective traffic management strategies. Additionally, addressing other sources of pollution, such as waste burning, construction, industrial activities, and firecracker use during Diwali, is essential.

The Delhi government has taken some initiatives to improve air quality, such as shifting polluting industries out of the city, introducing the compressed natural gas (CNG) programme, and setting new emission standards. However, more urgent and systemic long-term changes are needed to meet clean air standards and protect the health of Delhi's residents. With over two million children in Delhi already suffering from abnormalities in their lung function, the need for swift and decisive action to reduce vehicular emissions and overall pollution levels is paramount.

Pollution caused by traffic congestion

Delhi, the capital of India, has been struggling with hazardous levels of air pollution, which affects the lives of millions of people. The city's air quality continues to be severe, with PM2.5 reaching hazardous levels. According to the WHO, India has 14 out of the 15 most polluted cities in the world in terms of PM2.5 concentrations, with Delhi being one of them. Ambient air pollution in India is estimated to cause 670,000 deaths annually, and it particularly aggravates respiratory and cardiovascular conditions, including chronic bronchitis, lung cancer, and asthma.

One of the major contributors to Delhi's air pollution is traffic congestion, leading to increased vehicular emissions. During peak traffic hours, when average traffic speed drops, NO2 levels are significantly higher than during noon hours when traffic speed is higher. These congestion-related emissions worsen air quality, especially during winter when inversion layers trap pollutants close to the ground. Scientific studies have shown that at low speeds, vehicles burn fuel inefficiently and pollute more per trip. For example, a study found that at average trip speeds between 5 and 20 kilometres per hour, car pollutant emissions were up to eight times higher than when the average speed was 55 to 70 kilometres per hour. The traffic build-up in Delhi, with its extreme traffic gridlock, has resulted in a build-up of local pollution, particularly under stagnant conditions.

The Centre for Science and Environment (CSE) has confirmed that vehicles are the biggest contributor to particulate pollution in Delhi. Their real-time share of vehicular emissions in air pollution has increased to over 50% in early winter. Anumita Roy Chowdhury, executive director of the CSE, has stated that vehicular pollution is 40% of the problem and cannot be ignored if Delhi wants to achieve clean air standards. To address this issue, the CSE has highlighted the need for an integrated transportation system focused on improving public transport, as public transport usage in Delhi continues to decline.

The high cost of congestion also affects Delhi's workforce, with workers losing an estimated amount of their annual income due to traffic delays. Additionally, parking demand strains resources, consuming over 10% of urbanized land. The urban sprawl has increased travel distances, further contributing to the congestion and pollution. To tackle these issues, Delhi launched the Odd-Even Rule in November 2017, which is based on the Odd-Even rationing method, allowing cars with number plates ending in odd or even digits to be driven on alternate days of the week.

While vehicular emissions are a significant contributor to Delhi's air pollution, there are other factors at play as well. Local pollution sources in Delhi, such as construction, waste burning, industrial pollution, and energy usage, also play a role. Additionally, crop burning by farmers in neighbouring states, firecrackers during Diwali celebrations, and adverse meteorological conditions can further aggravate the pollution levels in the city.

The impact of Diwali celebrations

Vehicular emissions are a major cause of Delhi's poor air quality, contributing around 40% of the problem. However, the annual Diwali celebrations also significantly impact the city's air pollution levels.

Diwali, the Hindu festival of lights, is celebrated with firecrackers, the smoke from which releases harmful pollutants into the air. In 2024, Diwali celebrations caused Delhi's air quality to plunge into the 'severe' category, with a thick layer of toxic smog cloaking the city. This was due to the release of fine particles (PM2.5) and an increase in sulfur dioxide (SO2) concentration. The use of fireworks during Diwali resulted in 1.3 to 4.0 times the usual amount of pollutants in the air.

The poor air quality caused by Diwali firecrackers, combined with other sources of pollution such as vehicle emissions, stubble burning, and farm fires, poses a severe risk to the health of Delhi's residents. Ambient air pollution is linked to respiratory and cardiovascular diseases, including asthma, bronchitis, COPD, lung cancer, and heart attacks. The high levels of pollution during and after Diwali lead to an increase in hospital visits, with a higher concentration of outdoor pollution particulates resulting in a 20-25% increase in emergency room visits.

To mitigate the impact of Diwali celebrations on Delhi's air quality, the government has implemented several measures, such as the Odd-Even Rule, which allows cars with number plates ending in odd digits to be driven on certain days and even digit vehicles on other days. However, more integrated and year-round efforts are needed to address the city's air pollution crisis, including improving public transportation to reduce the number of private vehicles on the road.

The geographical location of Delhi

Delhi, officially the National Capital Territory (NCT) of Delhi, is a city and union territory in north-central India. The city is divided into two parts: Old Delhi, in the north, and New Delhi, in the south. New Delhi, the capital of India, was built during the 20th century as the capital of British India. The city of Delhi has a population of over 11 million, while the NCT is home to about 16.8 million people.

Delhi is located on the floodplains of the Yamuna River, straddling the river but primarily situated on its right bank, in the west. The city shares borders with the state of Uttar Pradesh to the east and the state of Haryana in all other directions. Delhi is landlocked and part of the Indo-Gangetic Plain, with little variation in elevation across the city. The Delhi Ridge, also known as the Lungs of Delhi, is all that remains of the Aravali mountain range in the region. The city is vulnerable to earthquakes due to its location on several fault lines.

Delhi's urban agglomeration, including satellite cities such as Ghaziabad, Faridabad, Gurgaon, Noida, Greater Noida, and YEIDA city, is known as the National Capital Region (NCR). With an estimated population of over 28 million, it is the largest metropolitan area in India and the second-largest in the world, after Tokyo.

Delhi's geographical location in the Indo-Gangetic Plain contributes to its poor air quality. The region lacks the geographical advantages of other parts of the country, with no sea breeze to disperse pollutants. The city's landlocked position and unfavourable meteorology cause pollutants to become trapped, particularly during the winter months when adverse weather conditions further worsen air quality.

The need for an integrated public transport system

Delhi's transport infrastructure is highly relied upon by the city and its people. The city has developed an efficient public transport system, with the introduction of the Delhi Metro in 2002, which has been undergoing rapid modernisation and expansion since 2006. Buses are the most popular mode of transportation, with 60% of commuters opting for them. Private vehicles account for 30% of the demand for transport, while the rest is met by auto-rickshaws, taxis, railways, and the rapid transit system.

However, Delhi faces significant challenges due to its poor air quality, which severely impacts the lives and health of its residents. Vehicular emissions are a major contributor to this issue, accounting for 40% of the problem. During peak traffic hours, when average traffic speed drops to 15 km/h, NO2 levels increase significantly, and congestion-related emissions worsen air quality. The city's geographical location also exacerbates the problem, as there is no sea breeze to disperse pollutants, and adverse meteorology further aggravates the situation.

To address these issues, there is a critical need for an integrated public transport system in Delhi. The current public transport system is costly for users, with higher journey times and frequent interchanges, making it less attractive than private transport. Experts believe that a robust public transport infrastructure, providing a comfortable, convenient, and seamless travel experience, is essential to reducing the number of private vehicles on the roads and, consequently, vehicular emissions.

The Delhi government is taking steps in the right direction by reviewing a Route Rationalisation Study carried out by the Delhi Integrated Multi-Modal Transit System. This study aims to provide people with reliable public transport within 500 meters of their homes and at a frequency of around 15 minutes. The introduction of air-conditioned buses, the revamp of bus shelters, and the integration of GPS systems in buses and bus stops to provide reliable information are positive initiatives. Additionally, the Delhi Transport Corporation (DTC) operates the world's largest fleet of CNG-powered buses, contributing to environmentally friendly initiatives.

Furthermore, app-based taxi services like Uber and Ola have become a convenient option for commuters, reducing the need for traditional taxis and offering auto-rickshaw booking services. Electric bicycles and scooters are also available for rent through vehicle-sharing apps, providing eco-friendly alternatives for shorter distances.

In conclusion, the need for an integrated public transport system in Delhi is evident. By providing a seamless, efficient, and environmentally friendly transportation network, Delhi can reduce its reliance on private vehicles, alleviate congestion, and significantly improve its air quality, ultimately enhancing the health and well-being of its residents.

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