Air pollution is, in my opinion, the biggest in major cities and some places without trees.
Speaking of trees, they actually have the ability to keep the air around them fresh and clean by absorbing the smog and other pollutants in it.
Cars and other fossil fueled machines are the main cause of air pollution for more than one hundred years.
So far, the trees are preventing this from getting worse.
There are other fossil fuels in the world but they remain untouched because they are much more pollutant than those being used today.
I do not know how much fossil fuel is used every year but air pollution is still a problem and a lot of people are finding ways to reduce the use of any more of it in the future.
To a surprise I seen and heard that diesel fuel is not flammable but for sure that is still trouble for the planet anyway.
Many ideas were introduced to make cars less pollutant.
There are cars that are electric which you can always plug in to keep it powered.
Solar powered cars which are fueled by light alone but the sun is always intermittent.
In the future, there will be cars that run on water and others on air alone.
Besides it is believed that fifty years from now, the fossil fuels we use today will be long gone and we would turn to these ideas.
Anyway, today's hybrid cars are designed and built today so I hope they do well.