In Sanskrit, Akash means “sky" or "space" and Mudra means “gesture.” This practice is a Asamyukta meaning “one” Hasta Mudra, where only one hand is required to preform this practice but both hands can preform this practice.
This practice allows us to unite the individual Consciousness with the Universal Consciousness, known as Atma meaning "Self" or Soul and Paramatma meaning "Primordial Self," "Self Beyond," the Creator or God.
This hand gesture is often used in Ayurveda which is a sister science to Yoga and is a form of medicine practiced in India to increase the air element as well as in the spiritual practices of Yoga to calm the mind during Meditation.
With this practice when the middle finger and thumb are slightly pressed together, this action is like acupressure allowing the sinuses to become unblocked and healed.
Hand gestures are a precise way of holding the fingers to create new energetic pathways for the flow of Prana for health and spiritual purposes.
Yoga poses help to elongate and strengthen the muscles of the body as well as to calm the mind for the deeper spiritual practices of Yoga.
Breathing exercises are a great practice to remove carbon dioxide, increase lung capacity as well as being a good preparatory practice for the deepest spiritual practice of Yoga, Meditation.
Meditation is the highest spiritual practice of Yoga which is why this practice is the most difficult practice to preform, but with correct knowledge and dedication, can be the most profound practice of Yoga.