As you know Aura is most popular subject among science field and also in world society nowadays. In Buddhism, there is an explanation about human Aura. Like this,
Aura is a reflection of someone's personality. As an example, if someone has strong aura, his/her personality is high and is very healthy. He /She is at a certain level in spirituality and loved by all humans and non- human (it is like a good attraction)
And also, Buddhism says that if someone's aura is weak, the personality also can be weak, and person can be unhealthy, can be sick quickly. (The probability of that happening is high.)
And Buddhism says how to improve our aura. People who have weak aura, can do meditation. In meditation, we improve our concentrating and also helps to clean seven chakras of body. If someone is vegetarian, it is also helps (but Buddhism never forces to be vegetarian. It is always choice). In addition to meditation, the aura can be developed by allowing positive thoughts like kindness, compassion instead of negative thoughts like jealous, hateful etc. (because aura is something which works with our mind and soul)
The color emitted by the aura changes in different emotions and different behaviors of the human body. for an example, stressed minded person and calm minded person has different aura colors. (A person can have several aura colors at same time.
And today scientists already found that we can find someone's personality traits using his/her aura colors. So, this is what Buddhism says about Aura.