One of the causes I care and worry about the most is how we millennials can contribute to reducing the high levels of pollution and waste in the world. Humans pollute: this is fact. Everything, from means of transport, to food production and factories in general, to cattle, construction, tourism and other services are responsible for increasing CO2 emissions and production of waste. Still, there are things we can all do to help the planet heal itself, and preserve the wonderful variety of ecosystems we have.

One of the things that I find most shocking is how unbreathable the air can be in big cities. Take London, for example. Oxford Street is one of the most polluted places in Europe. In 2015, in only four days it had surpassed the legal limit of air pollution for the entire year. But London, on the whole, is very polluted – there are too many people. If you walk on the street and you get home and clean your face with a cotton pad, it comes out black. If you blow your nose, it comes out black. If this is the effect you see on the outside, imagine how much damage you are making on the inside: your lungs, your blood, your cells.

Other cities in Europe and the world have the same problem, but thankfully, governments are actively taking initiative to improve the situation – more green spaces, fewer cars, more cycling lanes, renewable energy sources, more electric vehicles. But if individuals don’t change their bad habits, these general initiatives will not make such a great difference in the world. Not everyone recycles or buys reusable bottles or avoids plastic bags or checks the tags on the goods they buy to see if their makers are using sustainable materials and production methods.

Still, great initiatives exist, which give us hope. For instance, several supermarket chains around the globe have banned free plastic bags, making people buy them, or incentivising them to get the bigger ones that they can use again for future shopping. Plastic is one of the world’s biggest problems, as it does not disappear once it is produced. If not recycled or incinerated (which pollutes a great deal, too), it will end up in a dumping ground, or in the ocean. Scary studies claim that by 2050, if we do nothing about it, the ocean will have more plastic than fish. Furthermore, all the plastic in the ocean ends up being eaten by the fish that we later eat ourselves, which has terrible consequences for public health, as well as for aquatic life.

We see beaches and rivers in third-world countries with tons and tons of waste piling up for miles. This is bad for the people living close to these areas, not only because of the smell, but also because it ends up in the water they drink, transmitting diseases; or in the ocean, hence contributing to the destruction of entire water ecosystems.

Fortunately, more people are beginning to worry about this situation, and incredible initiatives such as the Mumbai Beach clean-up, where a great number of volunteers helped remove the waste from one of the most polluted beaches in the world, are becoming more common. This should be done everywhere.

However, this is not a problem exclusive to third-world countries, where poverty is the main reason behind the lack of more sustainable habits.

Last summer I visited Mallorca and Menorca islands in Spain. Like Formentera and Ibiza, in these two islands of the same archipelago you can find turquoise blue waters and paradisiacal beaches and beautiful mountain roads. What you see in the pictures is what you get in reality, minus the hundreds of other beach goers filling the sands. This is surely the problem: too many people go there, and don’t let their presence go unnoticed.

It is one thing when you see beaches in third-world countries filled with plastic and general waste, functioning like dumping grounds. But to see this is paradisiacal beaches in developed countries like Spain makes no sense – this was what motivated me to write this article to begin with.

There was plastic everywhere in some of them, left by the people on the boats, and those bathing on the beach itself. On one of the days, my friends and myself helped other volunteers do an impromptu cleaning and garbage collection. By the end of it, several containers were filled with plastic bottles, pieces of plastic, juice and soda packs, plastic bags, sandwich wrapping made of plastic and paper, gasoline bottles… you name it. It shocked me to see that beach-goers are not careful enough to take their litter with them, and that they would not even consider the fact that they were actively contributing to polluting a beach which was originally clean. It is not only a lack of respect for the other people visiting and living there, but also an unthinkable habit in the 21st century. Not to mention the fish and native animals that will end up eating this by accident. How civilised people can leave beaches and other public places so polluted nowadays is beyond me. Everyone drinks and eats at the beach, but if we clean up afterwards, it is not a problem, and not that hard to do.

Thankfully, there are several beaches that have volunteers nearly everyday collecting the garbage that others leave behind – if everyone cleans up after themselves, we could focus our efforts in helping other countries which do not have the resources to make this kind of initiative come to life, and in investing in large-scale cleaning programs to remove plastic from the oceans.

This kind of behaviour really needs to change if we want to help our planet preserve all its diversity. After all, we are the ones having to live with the consequences of pollution in the years to come. We should be protecting the Earth instead of damaging it.