How North India’s Smog problem is part of the larger Climate Change issue

It is that time of the year again when North India gets engulfed in a thick gloomy greyish-brown of doom called ‘smog’ that makes people living in this region earnestly yearn for those bright sunlit winter days of the past. Air quality in Delhi and surrounding areas have turned ‘severe’ and people are grasping for breath in the first week of November. 

Over the last few years, smog has increasingly impacted the North Indian states of Punjab, Haryana, Delhi and Uttar Pradesh. While most of the blame falls on the ‘stubble burning’ and ‘Diwali celebrations’ for the worsening quality of ambient air in these states, it needs to be highlighted that India’s smog problem is also part of the larger climate change issue. 

Vehicles are a Major Contributor

According to a recent investigation by the Centre for Science and Environment, among local sources, vehicles may have contributed the most to air pollution in Delhi for the week of October 21 to October 26. 

From October 21 to October 26, the national capital’s own contribution to PM2.5 levels was roughly 51%, or about half, according to the data. Vehicles contributed about 17% of Delhi’s PM2.5 concentration when the impact of other NCR districts and biomass burning were taken into account.

Over the course of the week, the daily percentage of emissions from vehicles varied between 49.3% and 53%. Residential sources came in second with 13%, followed by industrial sources with 11%, and construction with 7%.

This is a significant find as it is well known that vehicular emissions due to the burning of fossil fuels is one of the major contributors to global warming at present. 

Two Sides of the Same Coin: Air Pollution and Climate Change

There is an intrinsic connection between air pollution and climate change. The UNEP says that they are two sides of the same coin. In India, air pollution seems to get highlighted only when ‘smog’ like cases surface every year during the winter. But the fact remains that during this time of the year, multiple factors like ‘stubble burning’ and ‘winter conditions’ only amplify an already worsening air quality in the region that is silently contributing to global warming and vice versa. 

“The relationship between air pollution and climate change in the Indian context is obvious. The most important air pollutants like CO2, CO, black carbon and methane are either greenhouse gases or other forcings having high global warming potential or direct GHGs, contributing to global warming,” said Dr Partha J Das, Senior Climate and Environment Scientist who heads the ‘Water, Climate and Hazard Division’ of Aaranyak “On the other hand, the major contributors to global warming like CO2, Methane, O3, PM2.5, etc. constitute some of the main air pollutants in India.” 

The infamous Delhi Smog beyond ‘stubble burning’

Smog issues in India, including the infamous Delhi smog that covers New Delhi and its environs in the winter, are mostly caused by severe air pollution. The inherent air pollution brought on by businesses and factories, coal-fired power plants, road dust, vehicle traffic, the widespread usage of firecrackers during Diwali, and crop stubble burning in western India are the main sources of the ‘Delhi Smog’.

While much has been written and spoken about the stubble burning in states like Punjab contributing to the poor air quality in North India, primarily Delhi, there are other factors at play here and these have a connection with the larger climate change issue. 

“The stubble burning’s role in Delhi’s air pollution varies from 10% to 50% on average. The Delhi smog constitutes mainly of CO2, CO, Particulate Matter 10 (PM 10), Particulate Matter 2.5 (PM 2.5), SO2, NO2, O3 and NH3. Out of these, CO2 and O3 are GHGs, whereas CO indirectly enhances the GWP (Global Warming Potential) of other gases and therefore is also a climate forcing,” Dr Das said.  

“PM 2.5 consists of mainly black carbon or carbon soot that is emitted during the process of burning fossil fuels such as coal, petrol, and diesel as well as biomass and biofuels. It is the second major source of global warming after CO2 and is a short-lived climate pollutant (SLCP) responsible for nearly 50% of global warming to date,” Dr Das explained. 

He added, “Black carbon is not considered a GHG as it comprises particulate matter. But it has a high global warming potential, almost 460-1,500 times that of CO2. Therefore, it warms up the atmosphere by absorbing solar radiation and converting it to thermal radiation. Thus, it acts as a climate forcing.” 

“Black carbon or soot is majorly responsible for the accelerated melting of snow and ice and therefore glaciers in the Arctic and Himalayas as deposition of the soot particles result in a decrease of albedo increasing in warming of the snow-ice surfaces,” Dr Das further said. 

On the other hand, the repeated extension given to the coal-powered thermal power plants within 10km of the national capital region in terms of meeting SO2 and other pollution norms is only making matters worse. In a recent notification, the environment ministry extended the timeline to meet SO2 norms to December 31, 2027, for units that are scheduled to retire, and December 31, 2026, for plants that will continue operations beyond that period. It is well-known that SO2 through sulphate formation makes a significant part of PM2.5 and results in huge public health and economic damage. 

Burning Stubble in a Changing Climate 

The Indian Monsoon seems to have got extended to late October in recent years because of climate change. This has been witnessed as a growing trend over the last few years. Rainfall till mid-October delays the harvesting process in North India and when the rain finally ends it leaves farmers racing against time to finish harvesting and prepare the field for the next crop. What follows is a sudden increase in farm fires as the farmers set fire to the stubble in a bid to quickly get rid of them in a cost-effective manner. 

The government has tried to help by introducing harvesters and seeders but multiple ground issues that need to be addressed exist. 

“I had a discussion with a farmer and he told me that Paddy variety 1121 is not properly shredded by a combine harvester and they are resorting to the manual cutting of Paddy and paying about Rs 500 per day to farm labourers,” Dr M S Bhatti, Professor at the Department of Botanical & Environmental Sciences – Guru Nanak Dev University in Amritsar, said in an email to CFC India. 

Dr Bhatti also said that whether ‘happy seeder and other baler machines’ are easily available is another aspect that needs to be looked into.

“In my opinion, the solution lies in the total record of emission inventory (fuel to be burned) in a city on a daily basis. This may put light on their own contribution first. Pareto principle says first look out for 80% contribution as Punjab fires have contribution in the range of 3-30% (best guess). Cordon-type survey has to be done and all fuel/burning material inventory should be maintained,” Dr Bhatti further said. 

Late monsoon withdrawal is also not good in terms of stagnant weather conditions that lead to low wind speeds, descending air, and compressed boundary layer which favour rapid fine particulate matter formation and accumulation of pollutants, according to SAFAR.

The Climate Change Connection

Scientific studies from different parts of the world have found that changing weather patterns linked to rising global temperatures have resulted in a dearth of wind resulting in a rise in smog conditions. This has exacerbated a wave of severe air pollution and in a way connects climate change to smog. 

Researchers attribute the resilience of smog in Beijing during January 2013 to unusually stagnant air conditions brought on by climate change. According to a study published in the journal Science Advances, the air was the stillest in three decades during the heavy particulate pollution in 2013.  The study discovered that shifts in wind patterns across Asia in 2013 that failed to clear the air over northern China were caused by the melting of ice in the Arctic mixed with more snowfall in Siberia.

“In the long run, emission reductions of both pollutants and greenhouse gases are needed to mitigate the winter haze problem,” Mr. Wang, a co-author of the study, had said to the New York Times. 

In the case of North India as well, the smog problem seems to have a direct connection with local weather conditions and meteorological factors like temperature inversion and changes in wind speed and direction that have a substantial impact on the intensity, dispersion, and persistence of air pollutants. 

Multiple reports have been published about global wind speeds ‘slowing down’ on average over the last few years. India too has witnessed slower wind speeds in recent years and climate change has been attributed to this. 

Solution

Recent studies suggest that global action on carbon dioxide and SLCPs together is needed to meet the temperature goals in the Paris Agreement.

“Any attempt to reduce air pollution also helps in mitigating global warming and climate change. Therefore, mitigating air pollution and climate should lead to integrated programs, especially in polluted cities of India. Reducing ambient and household air pollution can also reduce emissions of carbon dioxide (CO2) and short-lived climate pollutants (SLCP), such as black carbon particles and methane, therefore contributing to the near- and long-term mitigation of climate change,” said Dr Das.