Delhi’s air pollution crisis has reached unprecedented levels, making it the most polluted city globally, according to WHO data. Residents are exposed to dangerous PM2.5 concentrations over 30 times the recommended safety limits, a staggering 3000% above safe levels. India’s poor air quality is now a leading public health threat, contributing to an estimated 1.67 million deaths each year and resulting in economic losses equivalent to 1.4% of its GDP. This environmental and health crisis has cost the economy around ₹2.6 lakh crore, significantly impacting productivity and labor availability.

Stubble burning and firecrackers have often been blamed for Delhi's air pollution crisis. However, a recent study by the Centre for Science and Environment (CSE) challenges this notion, showing that agricultural fires contribute only 1 to 3 percent to the city's air quality, with occasional spikes reaching 8-16 percent on certain days. In contrast, vehicular emissions emerge as the predominant source, accounting for nearly 50% of PM2.5 levels, while residential burning adds another 13%. 

Adding to the complexity, a report by the International Forum for Environment, Sustainability, and Technology (iForest), as cited by Livemint, claims that over 51.5% of the PM2.5 load in Delhi-NCR comes from residential cooking and heating using solid biomass, with residential cooking alone responsible for 41%. To address this, iForest recommends a 75% subsidy on LPG cylinders for low-income NCR families, estimated to cost under ₹7,000 crore annually.

Yet, this solution raises questions. The National Family Health Survey reports that 98% of Delhi residents already use clean cooking fuels, casting doubt on the 41% emission estimate from cooking. Additionally, an LPG subsidy to Delhi NCR may have limited impact, as a Council on Energy, Environment, and Water (CEEW) report states that 64% of Delhi’s winter pollution originates outside the city.

Then there is data from The SAFAR (System of Air Quality and Weather Forecasting and Research) which indicates that transport is the largest single source of emissions in Delhi, accounting for 41%. Industry contributes 18.6%, while re-suspended dust makes up 21.5% of the pollution load. The power sector accounts for 4.9%, and bio-fuel usage contributes just 3.0%onally, 

Furthermore, a study from IIT Kanpur ( IIT K )  identifies winter pollution sources, detailing contributions from secondary particles (25-30%), vehicles (20-25%), biomass burning (17-26%), and municipal solid waste (MSW) burning (9-8%), along with lesser contributions from soil and road dust.

This is all the data related to PM 2.5 while the and the Air Quality Index (AQI) reflects this intricacy by aggregating multiple pollutants such as nitrogen oxides (NOx), carbon monoxide (CO), particulate matter (PM10 and PM2.5), sulfur dioxide (SO2), and ozone (O3). In my analysis, I focus primarily on PM2.5, given its significant impact. According to the Central Pollution Control Board (CPCB), not all eight pollutants are monitored at every location; the overall AQI is calculated only when data for at least three pollutants are available, with PM2.5 or PM10 being essential.

Data from sources like CSE, IIT Kanpur, CEEW, SAFAR, and iFOREST offer diverse perspectives on Delhi’s air pollution, reflecting the complex and variable nature of air quality. These variations in findings do not imply that some data is accurate while others are not; instead, they highlight the multifaceted causes and fluctuating contributors to pollution. In this context, data-driven governance becomes essential for effectively tackling Delhi’s pollution crisis. By providing precise, location-specific insights, data enables informed and real-time decision-making. 

Overall, Transportation is a significant contributor to PM2.5 levels in Delhi's air pollution, as highlighted by the latest report from the CSE and SAFAR. Given this context, one might expect initiatives like the Odd-Even vehicle scheme and an increase in electric buses for public transport to be effective measures. But are they? NO. 

The Odd-Even policy in Delhi primarily targets private cars; however, a study from IIT Kanpur reveals that four-wheelers account for only 10% of the total PM2.5 emissions in the city. In contrast, two-wheelers, which are exempt from this policy, contribute a staggering 33% to PM2.5 levels—more than three times the emissions from cars.

Buses, which the government promotes for public transport, account for only 5% of PM2.5 emissions. However, they contribute significantly more to Nox emissions, comprising 27% of the total vehicular NOx output. This discrepancy underscores the need for a more nuanced approach in evaluating the environmental impact of public transportation options. 

The purchase of electric buses (e-buses) in Delhi has grabbed headlines and sparked political debate, but is there evidence that they effectively reduce air pollution? Vehicular pollution isn't just about tailpipe emissions; in fact, 70-80% of particulate matter (PM) from road transport comes from non-tailpipe sources like road dust and the wear of brakes and tires. While e-buses do help reduce nitrogen oxide (NOx) emissions, they fall short in addressing PM2.5 and PM10 pollution, which remains a significant problem.

Additionally, these e-buses run on electricity, more than half of which is generated from coal—a major pollutant. And at nearly double the cost of a CNG bus, e-buses are a pricey option. Given these factors, the most practical and cost-effective way forward may indeed be investing in CNG buses, which offer a more immediate and budget-friendly solution for cleaner air.

In response to inquiries about its actions to combat air pollution in Delhi, the Union government provided a comprehensive update on March 31, 2022 in parliament. Among the measures cited was the imposition of Environment Protection Charges (EPC) on diesel vehicles with engines of 2000cc or more in the Delhi NCR region, in compliance with directives from the Supreme Court in the landmark M.C. Mehta vs. Union of India case (Matter No. 13029, 1985). This measure underscores efforts to address vehicular pollution in one of India’s most affected areas.

The government’s odd-even vehicle policy restricts cars with odd and even-numbered plates to alternate days, applying the rule uniformly across all engine types. However, the Environment Protection Charge (EPC) policy allows wealthier individuals with high-capacity diesel vehicles to pay for the right to pollute, which contradicts the intent of fair pollution control. While the principle should be “polluter pays,” in practice, it has become “pay to pollute.”

Air conditioners are a major driver of both greenhouse gas emissions and urban heat. Globally, they account for around 10% of electricity consumption, contributing nearly 4% to overall greenhouse gas emissions. As heat pumps, ACs cool indoor spaces by releasing hot air outside, further raising outdoor temperatures. In India, the top 5% of the population owns 53% of all air conditioners, leaving the poor to bear the brunt of the heat generated by this consumption.

On the flip side, the poor are also the most affected by pollution. While wealthier individuals driving SUVs can afford air purifiers for their homes, offices, and cars, the poor lack this luxury. Additionally, stringent regulations on activities like biomass burning, construction work hours, and brick kiln operations disproportionately impact the livelihoods of the poor, while the wealthy remain largely unaffected.This reinforces a question posed by Mrs. Indira Gandhi over 50 years ago at the 1972 Stockholm Conference: “Are not poverty and need the greatest polluters?”

To address Delhi's pollution crisis, bold, data-driven policies are crucial. The city should learn from global counterparts, such as Paris, which has implemented a traffic-free zone, banning cars from the city center. Simply imposing a cess on diesel vehicle registrations promotes a "pay and pollute" mentality. Delhi requires more radical measures, such as banning the registration of all private diesel vehicles or, at a minimum, SUVs.

As a developing country, Delhi has long emphasized the historic responsibility of wealthier nations for pollution and the principle ofcommon but differentiated responsibilities in addressing climate change. Similarly, Delhi must adopt this approach in Domestic environmental policies. While the wealthy, who contribute to pollution through air conditioners and SUVs, can afford air purifiers for their homes and offices, it is the poor who suffer the most. They are forced to breathe polluted air and bear the brunt of livelihood losses due to pollution control measures like restrictions on biomass burning and construction activities. Delhi needs to develop data-driven policies that penalize the rich polluters and compensate the poor for their livelihood losses. A starting point could be the creation of a loss and damage fund for the poor, funded by imposing charges on air conditioners which are major greenhouse gas and HFC emitter.