In 2015, I had the good pleasure to take a long-term stay at my grandparents’ place in Costa Rica. They live high in the mountains and there is a steep winding road to get up to their place. The scenery is beautiful and I would walk down the hill to the road and then back up every morning.
The air is amazing in the mountains, but the emission controls in the country are not. When I would pass a car coming up the road, I would choke on the fumes until they were long gone.