Taking the ferry from Sierra Leone's only international airport to the city centre, once we had reached Freetown, the city did not waste any time pulling us right into its cacophonic madness of sounds, smells, and sweaty heat. An Indian chap we had befriended, and whose family operates businesses across West Africa, swiftly arranged an autorickshaw for us, whisking us away in the direction of our hotel, cautioning us that we were 'in for a ride'. His roaring laughter was drowned out by the honking.

I pondered over the best way to describe the city, and arrived at 'absolutely mental'. It was like somebody had had the idea of a city, but then lacked the time or material, and most certainly any sense of a plan. People were remarkably friendly though, not to mention almost exuberantly patient. Exploring the city, we usually finished the day at Roy's for sundowners. A Lebanese-owned restaurant that served fresh crab and cold beers, it provided an uninterrupted view of a stranded fishing trawler, and a beach littered with waste.

Heading in the direction of Conakry, capital of neighbouring Guinea, we decided to take a taxi instead of a ferry to get a better impression of what lay outside Freetown. Sierra Leone is not exactly on the tourist trail, and the plan had evoked images of an adventurous ride through a landscape of lush jungles interspersed with tiny villages where locals would welcome us with steaming cups of coffee sourced from the highlands.

Instead, the road to the border was flanked by an endless number of small-scale businesses and markets, distressingly interrupted by bulbous garbage dumps with makeshift settlements on top. The smell was abhorrent.

When people sometimes ask me what I take away from journeys such as these, it is not souvenirs or pictures that can easily be shared on social media. Instead, the impression that we are too many people on this planet.

Stopped every half an hour by a police officer in a faded T-shirt and no ID to show, demanding money to let us through, my annoyance gradually gave way to acceptance. This has become my coping mechanism to deal with the state of the world more generally - the way some berate others for flying too much. or eating meat. The sort of changes that will truly make a difference are much larger than most of us are willing to make.

At the border, we were ushered into the room of an official in military uniform, a set of neatly polished medals on his commanding chest, the only source of illumination a fluorescent tube with a lonesome fly buzzing about. The AC was sending a shivering breeze our way. But forms were swiftly filled out and our passports stamped, a cheerful welcome to Guinea - in French - offered.

The gentleman who guided us through the process needed to be paid. So did the lady who had checked our passports, and the other gentleman who had continued watching a video on his phone. When I said I was out of money to a guy who was eyeing the trunk for an impromptu inspection, he uttered a disappointed 'okay' and rejoined his friends in a makeshift tent on the side of the road.

From the border, the country continued where Sierra Leone left off, until it reached the undulating hive of activity that is Conakry. While Africa is itself responsible for only 5% of global plastic production, the continent is flooded by massive amounts of waste exported from developed countries. It means that not only do so many people have so much less, but they also bear the brunt of it so much more.

That's what we saw from our car window. And that's what we discussed once we had showered in our well-appointed hotel room. And that's what we flew home with, as we switched on the in-flight entertainment system and drank our complimentary soda from a cup - a plastic cup.