The Least Polluted City in the World Is…

Industry, Environmental Pollution, Smog, Sunrise

Image by Ralf Vetterle from Pixabay

What is pollution?

Pollution is the introduction of any substance, or energy, into the environment at a rate faster than it can be cleaned, dispersed, recycled, or stored in a less harmful form. The most common types of pollution are air pollution, water pollution, and land pollution, but there are lesser-known forms of pollution that can be just as harmful.

Air pollution

Smog and particulate matter (sometimes referred to as soot) are the most common forms of air pollution. 

Smog forms when emissions from burned fossil fuels react to sunlight and air. Burning fossil fuels has many uses – from powering factories to vehicles to converting energy into electricity to heat our homes. 

Particulate matter, on the other hand, refers to the tiny particles of chemicals, dust, or allergens that are carried in the air. The sources of smog and particulate matter are similar, with both come from sources that combust fossil fuels, such as coal, gas, or natural gas.

When these pollutants are released into the air, they can be detrimental to human and animal health. Particulates are harmful because they can penetrate deep into the lungs, causing respiratory diseases and even heart attacks

The way air pollution is measured is through the number and size of particulate matter in the air. Particulate matter that is 10 micrometers or less in diameter is represented as PM 10, and particulate matter 2.5 micrometers or less in diameter as PM 2.5. The higher the density of these particles in the air, the higher the risk.

According to the World Health Organization (WHO), approximately seven million people worldwide die because of air pollution. In addition to that, 90% of people on earth currently breathe unhealthy air. Air pollution is also detrimental to the planet as a whole, as it can destroy plants and trees. 

Water pollution

When chemicals or dangerous substances are introduced into bodies of water, they can be harmful to the ecosystem. 

Chemicals such as pesticides, sewage, and fertilizers from agricultural runoff, or even metals like lead, are considered hazardous water pollutants. These pollutants make their way into our drinking water and cause massive harm to marine life, avian life, and entire ecosystems.

Scientists use a variety of characteristics to determine water quality. Some of these include temperature, acidity (or pH), dissolved solids, and suspended sediment. Each measurement reveals something different about a particular body of water, and since these can vary widely, it can be helpful to track changes in the same body of water over time. 

Land pollution

Land pollution is the process of depositing solid or liquid waste on land or underground that leads to the contamination of soil and groundwater and threatens public health and quality of life. 

Most land pollution is caused by municipal waste, industrial waste, and household garbage.

Industrial waste forms a significant portion of solid waste, while hazardous waste is any liquid, solid, or sludge waste that contains properties that are dangerous or potentially harmful to human health or the environment. 

Industries generate hazardous waste from mining, petroleum refining, pesticide, manufacturing, and other chemical production, like tanning leather. Households can generate hazardous waste as well, including paints and solvents, motor oil, fluorescent lights, aerosol cans, and ammunition.

The best way to measure land pollution is often to test samples of dirt or land for soil contamination. Soil contaminants are a diverse list of chemicals and can include petroleum products, heavy metals, pesticides, fertilizers, and other chemicals. Knowing the area well and whether or not there are factories or landfills nearby will help narrow down what contaminants to look for.

Noise pollution

Regular exposure to elevated or unpleasant sound levels can lead to negative effects in humans and animals. Even though noise pollution is invisible, it can still affect the environment. Noise pollution includes loud sounds from planes, factories, traffic, and other sources.

Many forms of noise pollution are a part of our daily lives and we fail to even notice them anymore. Noise pollution such as car horns, construction sites, and office noise can all lead to stress, but noise pollution can also be the underlying cause of other serious health concerns like hearing loss, hypertension, and sleep disorders.

Noise pollution also affects wildlife. Ships cause underwater noise pollution and can upset whales’ navigation systems and feeding schedules, and kill other species that depend on the natural underwater sounds to guide them. Noise pollution can confuse or scare birds and other wildlife, and also makes wild species communicate louder, which can shorten their lifespan.

Loudness (also called sound pressure level, or SPL) is measured in units called decibels (dB). The average human ear can detect sounds that range between 0 dB and about 140 dB. Sounds that range between 120dB and 140 dB can cause pain to the human ear. For reference, the SPL in a library is about 35 dB, while the level inside a moving bus or train is roughly 85 dB.

Light pollution

Like noise pollution, light pollution is a form of waste energy that can cause adverse effects and degrade environmental quality. 

Light pollution occurs when there’s unwanted or excessive artificial light in a given area. 

Light pollution can cause quality of life issues for people such as sleep disturbances, but it can also affect animal life by changing their migrations patterns and feeding times. Newly hatched sea turtles, for example, rely on starlight bouncing off waves to steer them in the direction of the ocean. If there are street lights around, they often get confused and head in the wrong direction.

Who is responsible for pollution?

There’s a lot of debate over who is responsible for pollution and what can be done about it. 

Ultimately, pollution and our climate crisis have been attributed mostly to the fossil fuel industry and governments that don’t regulate them effectively. However, other entities are responsible, too. Banks and financial institutions who provide loans or invest in fossil fuel projects and other polluting industries, such as the plastics industry, are responsible, as well.

The five most polluted cities in the world  

Hotan, China

Hotan – a desert area in northwestern China – ranks as the world’s most polluted city. This is largely due to sandstorms that have been made worse by climate change. Hotan had the highest monthly PM2.5 averages worldwide from March to June 2020.

New Delhi, India

New Delhi is a densely populated city that struggles with air quality throughout the year. Many different factors contribute to its overall poor air quality, such as emissions from thermal plants and factories, fires on farms, and congested transportation networks. At its worst, according to IQAir’s 2020 World Air Quality Report, New Delhi’s PM2.5 levels averaged 157 micrograms per cubic meter in December 2020, exceeding the World Health Organization’s annual exposure guideline by more than 14 times.

Ghaziabad, India

The third most polluted city in the world, Ghaziabad, is also found in India. Part of the capital region of Delhi, Ghaziabad’s high levels of traffic and industry play a large part in its pollution levels, but the most prominent factor is its topography, which creates a sort of “dustbowl” leading to massive amounts of dust accumulating in the city without sufficient wind to blow it away.

Dhaka, Bangladesh

Dhaka is a very densely populated city with many vehicles and factories. Its pollution problems stem mostly from a lack of rigorous environmental regulations. This has led to the continued use of inefficient vehicles that use diesel fuel, like motorbikes and trucks, and industrial pollution from unregulated factories such as brick kilns which use unregulated fuel sources for power.

Aside from these two issues, there’s also the large problem of dust. High concentrations of dust are present across the city due to the quantity of open burning sites where garbage is burned.

Luanda, Angola

Over the last decade, Luanda has turned into an economic powerhouse. New opportunities and industries have exploded over the region, while millions of people have moved to the city for work. This has increased pollution in the area dramatically, and Luanda is now one of the most polluted cities in the world. With a PM10 level of 332 and a PM2.5 level of 182, it is dangerous to even breathe without a protective mask in Luanda. 

The five cleanest cities in the world

Honolulu, Hawaii

According to the American Lung Association, Honolulu, Hawaii has some of the cleanest air in the world. 

Hawaii’s trade winds carry air particulates out to sea, meanwhile, there are very few factories or commercial industries operating in Honolulu to disperse harmful particulates. Because the islands are isolated, there aren’t any hazardous particles blowing over from the mainland.

Zurich, Switzerland

The city of Zurich in Switzerland is known for its clean air, and that’s not by accident. Widespread use of efficient public transportation, instead of individual cars, helps to cut down on air pollution in the city. 

People in Zurich often cycle as a mode of transportation, and use trains, buses, and subways instead of driving. The city has also implemented strict waste management techniques which help residents to manage their garbage and recycling.

Helsinki, Finland

A city that tops most lists of “Most Livable Cities in the World” is Helsinki, Finland. 

The capital of Finland is hailed as sustainable and filled with great green urban areas and is also one of the least polluted cities in the world. Residents routinely use public transportation and bicycles for mobility instead of cars. It’s easy to walk and bike everywhere, with the city maintaining roughly 2,400 miles worth of bike lanes.

Calgary, Canada

With a population of more than a million, Calgary is still considered one of the cleanest cities in the world. 

This is largely due to its approach to waste management – its green composting program and waste management updates have reduced the amount of garbage going to landfills by 48%. And most of this is through something as simple as sorting out compost and recyclables.

Copenhagen, Denmark

In Europe, the Danish city of Copenhagen is among the least polluted cities in the world. 

It’s a sustainable city with a strong cycling culture that aims to keep people active. Almost half of Copenhagen’s residents use bicycles as their primary means of transportation. Aside from cars, there are few things in the area that cause dangerous air pollutants. Copenhagen is expected to become a zero-emission city by 2025 and hopes to see its emissions decrease by 20% by 2015.


Ready to help keep your city pollution-free?

To help keep your city clean and pollutant-free, you can learn how to make positive changes to the environment. One way of doing this is to get involved at a local level and speak to your elected representative about what they’re doing to encourage banks and governments to divest from fossil fuels

On a personal level, you can also consider what your daily credit card purchases are funding. To learn more about sustainable personal finance, or to apply for the Aspiration zero – our carbon-neutral credit card – reach out to Aspiration today! 

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