We are in a very fast growing world. Every day we have new technogly coming and as a human we like these changes. We are now so advanced using internet, mobiles, sattelites, nuclear power so many things. But we are not aware of decreasing oxygen level every day due to industry CO2, vehicles smoke etc.
Here I have found interesting technology Saving Trees. I was surprised to see this is happing in our world. Not sure itss in use in every country. Check below video you will be amazed!