Suffocate Today, COPD Tomorrow: How Dust, Ozone, Changing Weather Is Driving A Year-Round Crisis In India's Cities

By Surabhi Gupta

New Delhi: Air pollution in India, particularly in the national capital, is increasingly emerging as a year-round public health crisis rather than a seasonal winter problem, according to multiple analyses of air quality data, expert observations and medical evidence.

While Delhi’s winter smog has long dominated headlines, recent assessments of data from the Central Pollution Control Board (CPCB) show that high pollution levels persist throughout the year. Summer months, typically perceived as relatively cleaner, often record particulate matter concentrations far exceeding national and global safety limits. And, according to experts, summer pollution is largely driven by sources that are different from those driving winter smog.

Dr Hishmi Jamil Husain, environmental scientist, said, “Delhi’s air pollution has shifted from a seasonal problem to a year-round cycle. Winter pollution is driven by combustion sources and stagnant air, while in summer dust storms, high temperatures and photochemical reactions worsen air quality. Vehicular emissions, construction activity and climate variability further intensify pollution levels.”

Experts say the emerging pattern reflects a complex combination of local emissions, atmospheric chemistry, changing weather conditions and urbanisation trends, factors that are increasingly making toxic air a permanent feature of life in many Indian cities.

Pollution No Longer A Winter Problem

An analysis of CPCB data from recent years indicates that Delhi experiences elevated pollution levels from March to June as well, with dust and ozone emerging as key pollutants during the warmer months.

At present, the city is operating under Stage I of the Graded Response Action Plan (GRAP), with air quality falling into the 'Poor' category on four of the last seven days, a sign that unhealthy air conditions are not confined to the winter smog season. Particulate matter levels in summer illustrate the scale of the problem.

As of March 16, air quality remained in the ‘poor’ category across 17 cities, including Ghaziabad, Greater Noida, Gurugram, Hajipur, Ambala, Ballabgarh, Barbil, Bhiwadi, Bileipada, Kunjemura, Manesar, Nandesari, Pali, Singrauli, Tonk, Tumidih and Yamuna Nagar. Meanwhile, Korba recorded ‘very poor’ air quality, according to the latest air quality data.

The CPCB reported that the average PM10 concentrations in India during the months of March, April, May, and June of 2024 were twice as high as the National Ambient Air Quality Standards (NAAQS) limit, with concentrations of 179, 201, 248, and 195 micrograms per cubic metre (µg/m³) respectively. The NAAQS limit for PM10 (which includes PM2.5) for India is 100 µg/m³ daily; however, according to WHO guidelines, the maximum level of PM10 is 45 µg/m³.

The average level of PM2.5 in India was also significantly higher than WHO-recommended levels; for example, in May 2024, the average PM2.5 level in India was 92 µg/m³, far higher than either the NAAQS level of 60 µg/m³ or WHO's recommendation of 15 µg/m³.

Ozone, Delhi's Top Pollutant

Summer months can also have the highest Ground Level Ozone (GLO), due to heat and intense sunlight. In a hot environment like India's, photo-chemical reactions from sunlight create higher concentrations of ozone. Ozone pollution is becoming more prevalent in Delhi, as evidenced by this year's data.

A study by the Centre for Science and Environment (CSE) found that GLO was the lead pollutant in the capital on 16 days in February, indicating that photochemical pollution is emerging as a year-round concern.

Unlike particulate matter (PM, both 10 and 2,5), ozone is not directly emitted into the environment; rather, it is created through reactions between NOX (nitrogen oxides, NO and NO2) and VOCs (Volatile Organic Compounds — carbon-based gases released from paints, solvents, cleaners, and fuels) when exposed to sunlight. Much of the NOX and VOCs that produce ozone come from vehicle exhaust, industry, and fuel combustion. This means there is enough precursor gas (NOX and VOCs) for ozone formation in the atmosphere over Delhi-NCR most of the time, given that ozone is regularly found to be Delhi's top pollutant even in January.

Experts say this shift complicates the pollution challenge because ozone control requires reducing multiple precursor pollutants, rather than targeting a single emission source.

Dust, Construction, Burning Leaves: Just Urban Things

Rajesh Paul, environmentalist, said, “Air pollution in many north Indian cities is no longer just a winter problem. While winter smog gets attention, pollution levels now remain above safe limits for much of the year due to dust, vehicular emissions, construction activity and rising ground-level ozone during hotter months. This shift shows the need for year-round air-quality management rather than seasonal emergency measures.”

Environmental campaigner Bhavreen Kandhari also stressed that pollution has never been limited to winter. “Toxic air has never really been only a winter phenomenon, we are just finally acknowledging that reality,” she said. According to Kandhari, several overlooked sources contribute to pollution during the warmer months.

“Construction dust and road dust are major contributors. Another key issue is that cities don't have systems to manage fallen dry leaves between March and May, a lot of which gets burnt in the open as a result, releasing particulate matter and toxic gases,” she said.

What The Weatherman Won't Tell

Weather has an important influence on pollution levels, as well as emissions. Recent research has shown that weather can make up to 40 per cent difference in air quality in many Indian cities.

The study was conducted by Delhi-based research organisation Climate Trends, to determine the influence of meteorological factors on air quality in various Indian cities, using data from different CPCB air quality monitoring stations.

During the observation period, the researchers identified three primary meteorological conditions (low wind speed, excessive humidity, and stagnation in the atmosphere) that contributed to trapping pollutants near the earth's surface. Particulate matter that is released into the ambient atmosphere will stay near the ground until it is eventually forced to disperse into the atmosphere.

The study estimated that a shift to well-ventilated atmospheric conditions alone could reduce PM2.5 levels by 35-40 per cent, highlighting the strong role played by seasonal meteorology. However, while weather may worsen pollution episodes, scientists emphasise that emissions remain the underlying driver.

Southern Discomfort

Although Delhi remains the country’s most polluted major city, deteriorating air quality is no longer limited to the Indo-Gangetic Plain. Rapid urbanisation, construction activity and vehicular growth are causing pollution levels to rise across several Indian cities.

In many areas of Mumbai where redevelopment is underway, such as Lalbaug, the amount of construction debris being created constantly leads to dust contamination in the environment. Data indicates that the city's annual average PM2.5 has risen every year since 2025, suggesting that as air quality continues to deteriorate, there will be a higher proportion of people affected by pollution-related illnesses, even in previously less polluted cities.

Coping With COPD, Gasping For Air

Year-round exposure to polluted air is already evident to physicians in hospitals across the region as a result of the continual presence of air pollutants.

Dr Bharat Gopal, Senior Director and Head of Interventional Pulmonology at Medanta, said physicians are seeing pollution-related illnesses throughout the year. “Air pollution is no longer just a winter phenomenon. In clinical practice we are increasingly seeing pollution-related respiratory problems throughout the year,” he said.

“These include worsening asthma, Chronic Obstructive Pulmonary Disease (COPD) exacerbations, persistent cough and increased respiratory infections. Even during months traditionally considered ‘cleaner,’ background pollutant levels remain high enough to trigger symptoms in vulnerable groups such as children, the elderly and people with chronic lung or heart disease,” he added.

According to Dr Gopal, long-term exposure to particulate pollution carries severe health risks. “Continuous exposure to fine particulate matter like PM2.5 is extremely concerning. Long-term exposure is linked not only to chronic lung disease but also cardiovascular disease, stroke, lung cancer and metabolic disorders,” he said.

Evidence highlighted by the WHO suggests that persistent air pollution exposure can significantly reduce life expectancy and impair quality of life, he noted.

The Pollution Condition

Doctors’ associations say hospitals are already observing a surge in pollution-related conditions. Dr Rohan Krishnan, chief patron of the FAIMA Doctors Association, said there has been a noticeable rise in respiratory illnesses linked to pollution.

“We are seeing an increase in patients suffering from pneumoconiosis, exacerbation of chronic obstructive pulmonary disease and asthma, as well as people developing allergic rhinitis,” he said. Krishnan also warned that pollution-related allergies often lead to unnecessary antibiotic use.

“Many people confuse allergic cough and cold caused by pollution with infectious conditions and start taking antibiotics. This can create larger health challenges for the population over the next 10–20 years,” he said.

He emphasised the need for stronger policy measures to control pollution sources, particularly vehicle emissions.

Dr Meet Ghonia, pulmonologist and National General Secretary of FORDA, said, “Fine particulate matter like PM2.5 penetrates deep into the lungs and bloodstream. It contributes not only to respiratory diseases but also cardiovascular illness, stroke and metabolic disorders,” he said. “From a public-health perspective, long-term exposure significantly reduces life expectancy and quality of life in highly polluted regions.”

What You Don't Know Can Hurt You

Despite the severity of the pollution crisis, experts say India’s air quality monitoring network still covers only a small portion of the population. According to the State of India’s Environment 2026 report, only 15 per cent of India’s population, about 200 million people, live within 10 km of a continuous air-quality monitoring station. The remaining 85 per cent, more than 1.2 billion people, breathe air outside any measurable monitoring range.

Sharanjeet Kaur, deputy programme manager at CSE’s Urban Lab and one of the authors of the report, said this gap limits the country’s understanding of the real pollution burden.

India currently operates 562 continuous air-quality monitoring stations across 294 cities and 966 manual monitoring stations in 419 towns and cities. However, the monitoring network is concentrated primarily in large metropolitan areas.

Environmental expert Anumita Roychowdhury said the lack of monitoring in smaller towns creates structural inequities in environmental governance.

“Cities with multiple monitors can demonstrate progress, claim clean-air funding and frame action plans. But hundreds of smaller towns, many experiencing comparable or even higher pollution levels, have no real-time data at all,” she said.

Experts say the changing nature of India’s pollution problem demands a broader approach to air quality management. Policies have traditionally focused on winter particulate matter spikes, but the rise of ozone, dust and year-round pollution suggests the need for a more comprehensive strategy.

Roychowdhury said the next phase of monitoring should combine regulatory-grade monitors with low-cost sensors and satellite data to create a hybrid network capable of covering more locations. As urban areas are growing and moving where emissions source occurs, air quality monitoring stations may need to be relocated periodically due to shifts in emissions patterns.

Merry Crisis And A Happy New Fear

Taken together, the evidence suggests that India’s air pollution challenge is far more complex than the seasonal winter smog that typically dominates public attention. Numerous interrelated factors will create a situation where air quality pollution levels remain elevated the majority of the year due to effects from dust storms, construction activity, photochemical ozone formation, meteorological stagnation, and so forth.

For millions of Indians, particularly those living in large urban centres, breathing polluted air is becoming a daily reality rather than a seasonal emergency.

Dr Rohan Krishnan warns that unless sustained action is taken to reduce emissions and strengthen monitoring, the country may face a long-term public health crisis driven by chronic exposure to toxic air.