As per the Hindu Raksha Bandhan traditions, a Rakhi should be tied on the right hand of the brother. All Hindu rituals are carried out with the right hand as it is believed to be auspicious to start any activity in a positive manner.
In India, the left hand is considered inauspicious to conduct any religious work as it is used for cleaning chores. The Hindus have a strong belief in doing good things in the clockwise direction (Right to left) as it coincides with the universe.
Another aspect of using the right hand for religious ceremonies like tying a Rakhi is based on Ayurveda Science. This ancient system stresses the use of the right hand for Rakhi tying as it regulates Vata, Pitta, and Kapha doshas. When a rakhi is tied on the right hand of the brother by a sister, these elements of the human body get regulated resulting in well-being.
In Nadi Shastra, the human body has three Nadis – Ida, Pingala, and Sushumna. Pingala Nadi is on the right side of the body linked to masculinity and imparts efficiency, strength, and vitality.