For many nations, including India, air pollution has become a major issue. In North India’s Indo-Gangetic plains, hazardous air pollution has led to a rise in fog and haze.
Across its most recent study, the World Meteorological Organization (WMO) noted that air pollution and thick fog days during the winter months had increased across the Indo-Gangetic plains, home to over 90 crore people.
Fog Signals Human Impact
The duration of fog is no longer a typical seasonal occurrence, according to the paper, and it indicates the growing influence of humans on the environment. It is necessary to develop a plan to cope with this thick and hazardous fog, according to the experts who led this investigation.
In honor of the ‘International Day of Clean Air for Blue Sky,’ which is observed annually on September 7, this study has been made public. Promoting global collaboration to address the grave issue of air pollution is the aim of this day.
The world’s most fertile and highly inhabited geographical region is the Indo-Gangetic plain.
Pollution Drives Fog Increase
Although fog is a seasonal phenomena, the WMO claims that pollution from building, fires, the burning of livestock, and vegetative waste is to blame for the area’s growing fog.
Measures like prohibiting the burning of agricultural leftovers and encouraging the use of clean energy for public transportation, cooking, heating, and lighting are necessary to reduce air pollution.
The research makes it abundantly evident that it is incorrect to treat the climate problem and air quality as distinct issues. Both are interdependent and benefit one another, and the economy, agriculture, and general public’s health bear the burden of this vicious cycle.
Human Activity Fuels Fog
According to Barrett, Deputy Secretary-General of the World Meteorological Organization, human activities such as the burning of fossil fuels not only drive climate change but also release pollutants—like ground-level ozone, nitrous oxide, and black carbon—that further intensify its effects.
A vicious loop exists. Air pollution and climate change transcend national borders. The whole planet is in danger from them. The World Health Organization estimates that air pollution causes about 4.5 million premature deaths globally each year, with significant negative effects on the environment and the economy.
Dense fog causes significant disruptions to train and aviation services every year during North India’s winter season. At the same time, there are a lot of accidents on the highways because of poor visibility. The fog will become thicker over the next several years, if forecasters are to be believed. North India will see a surge in dense fog, particularly in the Gangetic plains.
Winter Fog Set to Rise
In addition, there will be more fog days throughout the winter months. Scientists from Canada and India have shown that by 2045, the amount of fog would rise by almost 57% during the winter months. At the same time, days with heavy fog will see a rise of up to 154%.
There are now 18 to 22 days of fog on average throughout the months of December through January, according to the Meteorological Department. However, you could have to endure a month and a half of thick fog in the next years. As a result, visibility will be quite poor during the winter months. Scientists predict that the primary causes of the rise in fog will be climate change, rising pollution, and greenhouse gas emissions.
Using the CMIP6 model, researchers from Victoria BC University and the Indian Institute of Tropical Meteorology (IITM) in Canada carried out this investigation.
Fog Intensity Forecasted Increase
According to the research, there is a chance that the number of foggy winter days would rise by 154% between 2015 and 2045 as a result of air pollution, climate change, and rising temperatures brought on by greenhouse gases. The fog will also be 57% denser at that hour.
The Terai regions of the Ganges have high levels of humidity throughout the winter, according to Dr. Deepti Hingmire, a scientist from Victoria BC University in Canada who participated in the study. In such a scenario, fog would become denser in the next years as a result of rising air pollution particles and rising temperatures brought on by climate change.
A research using the CMIP6 model indicates that by 2046, there will be less foggy days throughout the winter.
Climate Impact on Fog
Climate change-induced heat increases and pollution reductions brought about by pollution reduction measures will be the primary causes of this.
Based on reanalysis data and models of atmospheric characteristics, the study examined the impact of climate change on fog conditions on a wide scale across the Gangetic Plains (IGP) of North India, according to IITM scientist Ramesh Vellore, who participated in the research.
The research also made use of convolutional neural network (CNN) mapping for deep learning. This research will contribute to the Indo-Gangetic Plain’s fog perspective.
In Delhi, smog has taken the role of fog.
From 2016 to 2021, the Ministry of Earth Sciences conducted research on the chemical makeup of fog in Delhi and other parts of northwest India. The fog is now gray in hue instead of white and thick as it was before.
Simultaneously, the fog now smells strongly of acid. Rather than fog, which is full of contaminants, we might argue that Delhi now has smog. The majority of the particles in Delhi’s fog, according to studies done in the last five years, were chloride, sulfate, nitrate, calcium, and ammonium. The primary sources of all of these emissions are burning trash, automobile smoke, and construction-related activities.
Pollutants Alter Fog Color
The India Meteorological Department (IMD) says fog happens when water droplets condense significantly because of the cold and high humidity. In northwest India, natural fog is white, but the pollutants in the air cause it to change hue.
For instance, Delhi’s fog is often gray in color because of the smoke that cars create. According to the research, there are roughly 24% chloride particles, 23% calcium particles, 15% ammonium particles, and 14% nitrate particles in the fog in Delhi and the National Capital Region.
In Delhi’s fog, almost 14% of the particles were sulphate, 4% magnesium, and 3% sodium. Fluorides were at 1%, while potassium was around 2%.
In northern India, several hotspots for pollution have surfaced.
The WMO study also cautions about the rising airborne particles like PM 2.5. The bulletin’s 2025 issue features a study of particulate matter (PM 2.5) with a diameter of 2.5 microns or less in 2024 for the first time. Three distinct models based on data from 2003 to 2024 were used to conduct this investigation.
According to the report, dust from wind-blown deserts, forest fires, and particles generated by transportation, industry, and agriculture continue to pose a serious risk to human health.
Wildfires Worsen Air Pollution
According to the report, China has worked very hard to reduce air pollution. It is beginning to pay off. China’s PM 2.5 levels kept declining. However, northern India still has hotspots for pollution. Because of forest fire activity in Canada, Siberia, and central Africa, PM 2.5 levels remained above normal.
Nonetheless, the Amazon Basin registered the highest PM 2.5 particles, and the situation deteriorated there as a result of dryness in northern South America and record-breaking forest fires in the western Amazon area.
Scientists claim that wildfires are a significant source of particle pollution, and that as the temperature warms, the issue will only worsen, endangering ecosystems, infrastructure, and human health.
Delhi’s Rising Vehicle Pollution
According to Vivek Chattopadhyay, Principal Program Manager, Air Pollution Control, Center for Science and Environment, Delhi’s weather has not changed substantially in the last six months. The wind speed is still modest, and the weather is still steady.
The 1990s saw a sharp rise in Delhi’s car population after globalization, which exacerbated the city’s pollution issues. After many buses and cars switched to compressed natural gas (CNG) between 1998 and 2008, pollutant levels slightly dropped. Records show that throughout 2010 and 2011, Delhi’s air had between 200 and 250 parts per million of PM 10.
Delhi Air Pollution Trends
Between 2010 and 2011, the Central Pollution Control Board (CPCB) and the Air Quality and Weather Forecasting System (SAFAR) began monitoring Delhi’s PM 2.5 levels. This gave folks a sense of how things were becoming worse. According to CSE’s research, Delhi’s air pollution level stays in the bad or very poor range between October and January of 2018–2024.
The research also discovered that although the number of days with poor or very poor pollution has decreased as a result of government and institutional efforts to manage it, the number of days with pollution has grown. The average PM 2.5 concentration in the air on these days ranged from 180 to 190. Its concentration in the air should not exceed 60 micrograms per cubic meter, following the guidelines.