Why Mango Leaves are used in all festivals& functions in India
Mango leaves continue to release oxygen for a couple of days at least, after cutting them. That's why they are used in all festivals & functions to keep the air fresh, specifically when there are many people there.
The reason why Sanatana Dharma encourages us to tie Mango leaves to our doors.
In this video, a mango leaf is cut in a laboratory & kept under a microscope. The bubbles coming out of leaf is oxygen.
Our Rishis knew this millennia back and made it a part of our culture.