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Planet Earth has a pollution problem.
Air pollution factors into more than one in 10 (11.65 per cent) of all deaths globally and 368 million people rely on unsafe water sources. Every year, 12 million tonnes of plastic makes its way into the ocean – threatening marine life and the survival of its most delicate ecosystems – and, in 2021, the world pumped 37.12 billion tonnes of carbon dioxide into the earth’s atmosphere.
Be it air, water, or soil, it’s clear that whatever form pollution takes, it’s not only harming people – but the very world that sustains all human, plant, and animal life.
So, where is all that pollution coming from? To find out, we’re taking a look at the world’s top five most polluting industries and diving deep into the sectors most responsible for the world’s emissions, before honing in on the UK’s most polluting industries.
With the scope of the international and domestic industrial pollution problem established, we’ll then look at what can be done (and what the world is already doing) about it – while examining how the UK’s pollution problem compares to its overseas counterparts.
Before we dive into the most polluting industries worldwide, let’s recap why attempting to track, manage and reduce pollution is so important.
According to the World Health Organisation (WHO), ambient ( outdoor) and household air pollution accounts for the deaths of 6.7 million people every year, while unsafe water sources are responsible for a further 1.2 million deaths annually. As for contaminants in our soil, WHO estimates suggest that around 420,000 die every year from diseases resulting from acute or chronic food poisoning – meaning soil pollution also plays a role in the health and mortality of the world’s citizens.
Almost everywhere, people are breathing in air full of invisible – yet incredibly harmful – contaminants, with some countries suffering more than others. At the time of writing, for example, levels of PM2.5 (a way of measuring particulate matter pollution in the air) in Pakistan’s Karachi were almost 13 times the maximum level the WHO recommends.
Pollution can damage ecosystems, disrupt food chains and lead to the decline – and eventual extinction – of whole species. While other forms of pollution also exist – including light, noise and even visual – we’ll be focusing on the industries that contribute the most water, air and soil pollution. We’ll also be placing greenhouse gases (a subset of pollution) at the heart of our analysis – particularly given their starring role in the world’s ongoing climate emergency.
Air pollution includes particulate matter (tiny solid or liquid particles in the air), as well as harmful gases such as nitrogen dioxide, sulphur dioxide, and carbon monoxide, heavy metals, and volatile organic compounds (VOCs). Air pollution can lead to acid rain, which harms soil and corrodes buildings and infrastructure. Air pollution has been linked with lung cancer, heart disease, and a litany of respiratory diseases.
And, of course, there’s one form of air pollution with a particularly disproportionate effect on our planet’s prospects – greenhouse gases. The largely human-caused over-production of these gases – which occur naturally in our atmosphere to trap heat and make earth liveable – is leading to the gradual warming of our planet. This is causing sea levels to rise, triggering extreme weather events, and, ultimately, putting our collective future at risk.
Pollution of the nutrients in water bodies, for instance when lakes, rivers, and oceans are contaminated by chemicals, plastics, sediment, radiation, pathogens, or chemical and oil spills, can lead to algae blooms; whose toxins are harmful to aquatic and human life. Water pollution can lead to water-borne diseases such as cholera and dysentery. And that’s just pollution’s effects on humans.
Soil pollution occurs when a contaminant – be it chemical, industrial, oil-based, organic, or even nuclear – affects crop yields and compromises soil fertility, posing a serious risk to entire nations’ food supplies.
The top five most polluting industries – organised by the amount of greenhouse gas emissions they’re responsible for – are:
To inform these rankings, we used statistics from Our World in Data, in conjunction with a variety of other cited sources. Our World in Data provides comprehensive CO2 and greenhouse gas emission data – sorted by fuel and industry type – up to 2021 (the latest available), with some data stretching back to 1750.
Now, let’s unpack each of the world’s top five most polluting industries, one by one, to develop a deeper understanding of how they’re contributing to the global climate problem.
The most polluting industry on the planet, the generation of energy using fossil fuels accounts for the emission of around 37.12 billion tonnes of carbon dioxide into the earth’s atmosphere.
According to the UN, the energy sector alone is responsible for around two-thirds of all human-activity-related greenhouse gases. But, when it comes to their capacity to pollute, some sources are more culpable than others.
Worst among them? The coal industry, which in 2021 was responsible for 14.98 billion tonnes’ worth of CO2 emissions, spearheaded by the biggest global coal consumers China, India, the US, Germany, and Russia.
Oil contributed 11.84 billion tonnes in the same year and gas 7.92 billion tonnes. Flaring – a practice that involves burning the excess natural gas associated with oil extraction – doesn’t produce useful energy but, since it’s part and parcel of the cultivation of oil as an energy source, we’ll include the 416.53 million tonnes of CO2 flaring accounted for in 2021, too.
That the energy sector is the world’s most polluting doesn’t come as a huge surprise – especially when you consider how much the world needs it. Whether it’s to light our workspaces, heat our homes, cook our food, or power our devices, without energy our daily lives – as individuals, professionals, and global citizens – would come grinding to a halt.
The sector’s massive contribution to global pollution also makes sense when you consider how much of the world’s energy needs are powered by fossil fuels (such as coal, oil, and natural gas). At least 29 countries source more than 90 per cent of their energy from fossil fuels, with some countries – including Saudi Arabia, Brunei, Oman, Qatar, and Kuwait – relying on them for 100 per cent of their energy use.
That said, it’s not all doom and gloom. Many countries are investing heavily in renewable energy sources – such as wind, solar, and hydropower – to wean their energy sectors and economies off an unhealthy dependence on fossil fuels.
While transportation isn’t the most polluting industry, the 8.43 billion tonnes of greenhouse gases trucks, cars, and planes chugging their way across our cities and countries emitted in 2019 make this sector the second-worst offender for pollution.
But why? Well, most vehicles in the transportation industry are powered by internal combustion engines, which rely on the combustion of fossil fuels to generate power.
These engines mix petrol or diesel fuel with air and ignite the mix to drive the vehicle’s wheels (or, in the case of planes, propellers). When we need to get somewhere, this combustion process – which emits CO2, nitrogen oxides, particulate matter, and other pollutants – is great. For our environment, though, it’s toxic.
Of the vehicles most at fault for the transportation industry’s emissions problem are cars and vans (which made up 48 per cent of the sector’s CO2 output in 2022), followed by heavy freight vehicles (16 per cent), medium freight vehicles (9 per cent), and international shipping (10 per cent). Bus (6 per cent) and rail (1 per cent) transport also added to the transportation industry’s total CO2 emissions in 2022.
Although international and domestic aviation travel contribute just 6 and 5 per cent, respectively, to the globe’s travel-related carbon dioxide emissions, aviation is implicated in a different kind of greenhouse gas – nitrogen oxides (NOx).
During jet combustion, aeroplanes produce NOx, considered one of the most important greenhouse gases, after carbon dioxide and methane. Then, when at cruising altitude, they release a steady stream of these nitrogen oxides into the atmosphere, where the chemicals linger and contribute to particulate matter formation in the upper troposphere. Global aviation’s role in pollution creation has been linked to causing 16,000 premature deaths every year.
The third-most polluting industry – which pumped a staggering 6.3 billion tonnes of greenhouse gases into earth’s atmosphere in 2019 – is manufacturing and construction.
The manufacturing and construction sector is a big emissions-producer because it relies on a huge, and near-constant, supply of (usually fossil fuel supplied) energy. Cranes, diggers, the freight vehicles required to ship materials and equipment from one site to another; it all adds up to an enormous environmental impact.
What’s more, many manufacturing processes involve high-temperature operations, chemical reactions and other industrial processes that release emissions. The production of cement, for instance, is especially culpable; according to Our World in Data, cement was responsible for 1.67 billion tonnes’ worth of CO2 emissions in 2021 alone.
Worse still, the construction industry’s impact on global emissions is a growing problem. The 2022 Global Status Report for Buildings and Construction (released at COP27) found the sector responsible not only for over a third (34 per cent) of the world’s energy demands, but around 37 per cent of energy- and process-related CO2 emissions in 2021.
Construction- and manufacturing-related emissions tend to be a large part of the pollution problem in developing countries, in particular. As we explored in our guide to the most polluted cities (and countries) in the world, India is an especially egregious example.
Industrial sources and construction combine for over half (51 per cent) of India’s emissions – a problem we see repeated across similarly well-populated and industrialised (yet developing) countries, such as Pakistan and Malaysia.
The agriculture industry was responsible for 5.79 billion tonnes of greenhouse gas emissions in 2019. One cause of agriculture’s pollution record is as a result of soil being improved and worked in order to cultivate produce. How manure is handled and managed, for instance, contributes, as do practices such as conventional tillage and poor soil management. Similarly, the application of synthetic fertilisers can release nitrous oxide into the atmosphere.
Agricultural farm practices are also energy- and land-intensive. The process of creating more farmland – which usually requires razing swathes of natural forestry, and the CO2-absorbing properties they provide, to the ground – only exacerbates the issue.
What’s more, agriculture owes a lot of its emissions to meat production: specifically, the methane produced by cows, sheep and goats. Their specialised stomachs (designed to allow them to digest grass) also lead to a process called enteric fermentation, which – combined with these animals’ penchant for flatulence – produces a lot of methane (a greenhouse gas).
That’s not to say it’s meat’s fault alone. Even the production of rice is to blame, in that the flooded conditions of rice paddies create anaerobic conditions for methane-producing bacteria to thrive. This makes the biggest rice-farming countries – China, with 149 million tonnes of milled rice produced in 2021/22, as well as nearest rivals India and Bangladesh – culpable. Although the overall statistics suggest that India, globally, is the world’s biggest CO2 emitter from agriculture.
When land use is taken into account, though, Brazil tops the list of highest overall global agricultural emissions. In 2022, Brazil lost 1.7 million hectares of forest – more than any other country in the world – while between 2020 and 2021, Brazil created an extra 3.27 million hectares of agricultural land for a total of 86.67 million hectares across the country – with its native rainforests no doubt making way.
Once the agricultural industry has produced all that food, it still needs to get to our plates.
It’s little surprise, then, that the food retail sector follows agriculture as the world’s fifth-most polluting industry. In 2021, the food supply chain – which includes food processing, transport, packaging, and retail, but not food production, as that was considered in the agriculture section – pumped around 3.1 billion tonnes of CO2e (carbon dioxide equivalents) into our planet’s atmosphere.
This comes from the energy required to refrigerate and freeze perishables, the vehicles relied on to transport them hundreds of miles, and the reliance on single-use plastics and other unsustainable packaging materials to serve them up. (Not to mention the amount of energy food distributors, sellers, and supply chain partners need to operate.)
Research by London South Bank University shows that refrigeration accounts for around 50 to 60 per cent of a supermarket’s electricity needs – indicating it’s not only food’s production that emits greenhouse gas, but the way it’s stored and kept fresh.
And that’s without even taking food waste into account. Food waste emissions are responsible for a further 2.1 billion tonnes of CO2e, with uneaten food – whether lost in the supply chain, or wasted by the consumer – responsible for 6 per cent of all greenhouse gas emissions globally.
We’ve explored pollution’s global picture. But what does the data say about the UK’s contribution to the pollution problem? Let’s take a look.
In the UK, human-made air pollution is responsible for between 28,000 and 36,000 deaths every year, leading the government to label it “the largest environmental risk to public health”.
The cost isn’t only to our health, either – but to our economy. Between 2017 and 2025, air pollutants (fine particulate matter and nitrogen dioxide) are projected to cost the NHS and social care system £1.6 billion.
So where does the UK’s pollution come from? According to data from Public Health England and Health Matters, that depends on the specific pollutants involved:
As for the total emissions picture, the UK – according to 2023 data from the Office of National Statistics – emitted a total of 502 million tonnes of carbon dioxide between 2020 and 2021.
Our World in Data reports the UK’s total 2021 emissions as 5.2 tonnes per capita – so around a third of Canada (14.3), the US (14.9), Australia (15.1), but more than many of our European neighbours, including Portugal (4), Switzerland (4), France (4.7), and Spain (4.9).
According to the aforementioned ONS data, the most polluting industries in the UK are consumer expenditure, energy, manufacturing, and transport.
Sky News – which reported that 15 companies paid to emit a total of 67 million tonnes of carbon dioxide, or a sixth of the UK’s total CO2 emissions, in 2019 – found that nine of these 15 companies are energy generators that rely on carbon-based fuels.
The companies most culpable were:
The most polluting industry in the UK is consumer expenditure, which is a bit of a tricky one to define. That’s because ‘consumer expenditure’ relates to many different activities – including travelling and heating homes – and thus encompasses emissions created by several different industries, including energy, transport, and manufacturing.
Despite this lack of clarity around its exact definition, the Office for National Statistics (ONS) stated that in 2021 (the latest data available) consumer expenditure accounted for 134,761 million tonnes of carbon dioxide emitted in the UK. This equated to just over a quarter (26 per cent) of the total emissions the country was responsible for in 2021.
What’s more (and something that, as we’ll soon see, is a trend of the UK’s most polluting industries also being the most reliant on fossil fuels), the consumer expenditure sector accounted for over a third (35.48 per cent) of the UK’s fossil fuel energy share.
Despite being the worst offender globally, the energy sector is only the UK’s second most polluting industry. Still, it contributes more than its fair share of the country’s emissions, taking credit for for 86,080 million tonnes (17 per cent) of the total CO2 the UK emitted in 2021.
Despite the energy sector’s high pollution statistics, the UK did derive 135.0 terawatt hours (TWh) of electricity in 2022. This accounted for 41.5 per cent of the country’s total electricity from renewable sources in 2022 – up from 39.6 per cent in 2021.
What’s more, in 2019 the UK passed a net-zero emissions law, stating its intention to become a net-zero country by 2050. (And, in the process, becoming the world’s first major economy to do so.) Going forward, we should expect to see renewable energy sources playing an ever-more integral role in the UK’s electricity-generation needs.
Accounting for almost 17 per cent of the UK’s fossil fuel share – and over 16 per cent of its total emissions – is the manufacturing industry.
In 2021, UK manufacturing emitted over 81.5 million tonnes of carbon dioxide. Among these, chemical production was the biggest contributor; accounting for 18 per cent of the UK’s total manufacturing emissions in 2019. Other offenders include steel – which relies on emissions-intensive equipment and materials, such as blast furnaces and coking coal – and cement.
Fortunately, though, the UK’s manufacturing emissions are trending down, historically – a reflection on both the gradual decline of the industry, as well as the country’s gradual gravitation towards renewable alternatives. The UK’s manufacturing emissions have decreased steadily: falling by almost 40 per cent between 1990 and 2021.
In 2021, the UK’s transport sector was responsible for around 56,753 million tonnes of carbon dioxide into the atmosphere – around 11 per cent of the country’s total emissions. Transportation in the UK also made up 13.31 per cent of its total fossil fuel energy share.
Like the manufacturing industry, however, the UK’s transport-related emissions are trending downwards. The sector’s emissions fell by a significant 28 per cent in 2020 according to the ONS, before a further 9 per cent reduction in 2021.
Analysis of the most polluting industries – both globally and in the UK – paints a bit of a bleak picture. From heating our homes and getting to work to putting food on the table, we’re almost always supporting at least one of the top emissions-producing sectors.
But that doesn’t mean there isn’t anything we – both in an individual and a collective sense – can’t do about it. So let’s take a closer look at what we need to do to move forward.
While there’s plenty you can do on a personal level to curtail the impact of the planet’s most polluting industries (a set of strategies we explore at length in our guide to how to be more eco-friendly), a great bulk of the responsibility lies with governments.
Specifically, their ability to introduce and implement policy changes.
How might this look? Well, in the energy sector for example, governments can impose carbon pricing mechanisms (such as carbon taxes or cap-and-trade systems) to incentivise energy-producing companies to reduce their environmental footprint. Renewable energy mandates and subsidies can also encourage companies to adopt more sustainable ways of generating power – and shuck the age-old reliance on fossil fuels.
Some countries already leading the way in terms of renewable energy policies include Uruguay (which generated 91 per cent of its energy needs from renewables in 2022), Sweden (which reached its target of 50 per cent renewable energy in 2012, almost a decade ahead of schedule), and – perhaps surprisingly – the UK. The UK’s thriving offshore wind sector already powers more than 7.5 million homes. And, by 2030 – as part of the government’s ambitious plan to decarbonise the UK’s power system by 2035 – that number is expected to quadruple.
As for the transport industry, policy changes could include fuel efficiency standards and emissions regulations for vehicles. Electric vehicles (EVs) are already the focus of much governmental debate, with countries flocking to encourage their adoption through tax credits, incentives, and infrastructure development. In the UK, for instance, the government has set targets for 100 per cent of new car sales to be electric by 2035.
Other policy-related changes governments can make to curtail transportation emissions include investing in public transport, and promoting walking and cycling through marketing campaigns. Luxembourg, for instance, made public transport free to use in 2020 (though it does have the benefit of being Europe’s richest country)in an attempt to shed its unwanted status as Europe’s most car-reliant population (at that time, it had 696 cars per 1,000 people).
In the agricultural industry, policy changes could include regulations of methane emissions from livestock and manure management, and the promotion of sustainable agricultural practices through subsidies and incentives. While in the food retail sector, positive impact can come from imposing energy-efficiency standards for refrigeration and lighting – as well as reducing food waste through incentives and regulations.
The Australian state of Victoria, for example, has introduced a circular economy policy (titled “Recycling Victoria: a new economy”) designed to halve its food waste by 2030 – cutting it from its 2020 total of 2.4 million to 1.2 million in just a decade.
Finally, policy changes in the manufacturing industry could take the form of building codes and standards prioritising energy efficiency and emissions reduction, as well as the promotion of carbon capture and storage (CCS) technologies.
Technology – particularly artificial intelligence – is arguably the most powerful force shaping our collective lives and futures. And, when it comes to curtailing the emissions of the most polluting industries, technology has a big part to play.
Among the technology shaping the renewable reform of the energy sector, for instance, are advancements in energy storage – such as batteries and pumped hydro storage – for retaining excess power produced and funnelling it back into the grid. What’s more, smart grids can combine sensors, data analytics and automation to reduce energy losses – and, through optimising how energy is distributed, lower emissions. Many electricity providers in 2023, for example, encourage consumers to use energy during off-peak hours: incentivising them to save by capitalising on renewably sourced energy.
Alongside EVs, the transport industry’s technological advancements include the rise of autonomous vehicles and vehicle-to-vehicle communication systems. By enabling the wireless exchange of data between cars and road infrastructure, these systems can reduce traffic congestion and improve fuel efficiency – thereby lowering emissions.
Developments in alternative fuels – including biofuels, hydrogen fuel cells, and synthetic fuel – are already offering increasingly attractive substitutes to traditional petrol and diesel. Early data already suggests that synthetic fuels can achieve CO2 reductions of up to 90 per cent, with the market expected to be worth $22.5 billion by 2031.
In agriculture, precision-farming technologies (such as GPS-guided tractors and drones) are on the rise. Through high technology sensor and analysis tools, precision farming can enable farmers to streamline how they use resources, and – by limiting chemical use – reduce emissions associated with pesticides and over-fertilisation.
One technological advancement in the manufacturing industry is the development of low-carbon construction materials: such as low-carbon concrete and sustainable insulation. It’s something many countries are already moving to enshrine in law, with Finland introducing legislation for low-carbon construction on 1 January 2024 and Danish law requiring new buildings over 1,000 sqm to meet with an emissions cap of 12 kg of CO2 per sqm per year.
It’s a question so common – yet complicated – that it’s become a political hot potato: does the responsibility for curbing emissions lie on the individual, or on big business?
The answer, in truth, is both – so let’s break down what each party can bring to the table to mitigate the impact of the world’s most polluting industries.
Individual responsibility for tackling climate change includes:
However, the onus is also on businesses to do their bit. This includes:
It’s difficult, in truth, to summarise a problem so sprawling and complex as industrial pollution.
While it’s easy to condemn the inordinate amounts of carbon dioxide sectors like energy, construction, food retail, agriculture, and transport produce around the world – billions upon billions of tonnes – it’s also easy to forget how much we rely on them in our day to day lives. From keeping us warm in winter and getting us to work to building the very homes we live in, these industries are so crucial that we take them for granted.
In other words, there’s no alternatives for the shelter, food, warmth, light these industries offer us – but there is an alternative to how they operate. By switching to more renewable energy sources, adopting more resource-efficient technologies, and lobbying for more impactful political and legislative changes, a less emissions-intensive future does exist.
Both individuals and corporations have a responsibility to curb industrial pollution. But it’s down to companies like RWE, Uniper, EPH and EDF – which, together, emitted almost 28 million tonnes of CO2 in a single year – to make the biggest changes. To take responsibility, take ownership, and take the reins of change in both hands.
If we, as a society, can curtail the amount of emissions, pollutants, and contaminants our industries are putting out, prizes await. Big ones, too – including the health of our population, the diversity of our animal and marine life, and the eventual reversal of the climate crisis, among others.
The energy industry is the most polluting in the world, accounting for around 37.12 billion tonnes of greenhouse gas emissions every year. The biggest culprits here are the burning of fossil fuels – coal, oil, and natural gas – which are used to generate energy for a range of domestic and commercial purposes.
At home, energy is used mostly for heating and cooling systems, household appliances and hot water but also lighting and cooking.
In terms of commercial uses, energy, as well as being the world’s most polluting industry, also powers all of the planet’s other most polluting sectors. It’s unsurprising, then, that energy is the most polluting industry in the world – because its applications are limitless.
According to Our World in Data, the UK’s 5.2 tonnes of per-capita emissions in 2021 rank it 65th among the globe’s full list of countries and territories. Of course, emissions are just one part of the pollution problem. Particulate matter (PM2.5) is another way of measuring air pollution levels and in this metric, the UK ranks 101st out of the 131 countries and territories according to air purifier supplier IQAir.
In 2022, the UK registered an average PM2.5 concentration of 8.9μg/m³ – 1.8 times more than the WHO annual air quality guideline value, but better than many other European countries, including Belgium (10.8μg/m³), France (11.5μg/m³), Poland (16.3μg/m³).
The UK’s emissions counterparts are on a par with places such as Seychelles (5.3μg/m³), Turkey (5.3μg/m³), the British Virgin Islands (5.1μg/m³), and Denmark (5.1μg/m³).
Generally, yes – although that depends on the industry. In the energy sector, for example, renewable energy, like solar, wind or hydropower, is a sustainable alternative to fossil fuels like oil, natural gas, and coal. While in the transportation industry, electric and hybrid vehicles can replace traditional, petrol-reliant cars.
In sectors like manufacturing and food production, it’s less about like-for-like alternatives, and more about better practices. In food production, an emerging alternative to the mainstream – called regenerative agriculture – is gathering momentum. It focuses on practices like crop rotation and cover cropping, as well as on organic farming methods to improve soil structure and sequester carbon. Vertical farming and hydroponic systems – which allow farmers to cultivate crops year-round, and reduce the need for water and land resources – are another sustainable agricultural alternative.
Lean manufacturing principles – which aim to eliminate waste and boost efficiency – as well as a focus on responsible product sourcing, sustainable materials, waste reduction and green manufacturing technologies (such as 3D printing) can help to reduce pollution as a result of the manufacturing sector.
In 2019, the UK became the world’s first major economy to pass a net-zero emissions law – pledging its commitment to becoming a net zero country by 2050. This superseded the UK’s previous promise (enshrined in the Climate Change Act 2008) to cut its emissions by 80 percent by 2050, from 1990 levels.
Despite leaving the EU, the UK has committed to maintaining the EU’s environmental standards and pollution control policies – and existing EU environmental law continues to have effect in UK law. This includes the Industrial Emissions Directive (IED): EU legislation aimed at reducing industrial pollutants, and promoting energy- and resource-efficient tactics and techniques.
In August 2022, the UK also announced a new framework (entitled “Best Available Techniques”) to enable industry and regulators to work together – ”and apply up to date, challenging standards when it comes to reducing harmful emissions”. Essentially, the framework requires any industrial facilities seeking a permit from environmental regulators to use the best techniques available to minimise their greenhouse gas emissions.
