Kundalini Yoga - Why wear white?
When attending a Kundalini Yoga class you will see a lot of people chose to wear whatever they choose to wear, in whatever colour they wish to wear. But you will also see people wearing white and covering their head. This means wearing white isn't a mandated rule, its a suggestion based on colour therapy. According to Yogi Bhajan when you choose to dress with grace, dignity, modesty, and elegance, it can strengthen your projection and become a tool to help you expand your consciousness.
Expand Your Aura
Expanding your aura increases your openness and neutrality, this expansiveness is created by wearing graceful clothing that is white or ivory, made from cotton, silk, wool, or other natural fibers.
Wearing white creates a powerful interface between you and your environments as it expands your aura. The spectrum of light energy that makes up the color white contains the energies of all colors. By wearing white, all the colors are available to support and enhance the aura and the Chakras.
Natural fibers are energy conduits interacting with your surroundings conducting prana inward and filtering negative or energy.
Projection and Impact
Elegant, white dress makes you visible to people giving you projection and impact on your surroundings. Making an impact on those around you provides a connection and they will remember you due to that impact through projection. Dressing in white can expand your energy increasing your projection. When your style of dress is a reflection of your own commitment to your inner reality, it creates a subtle communication with other people. The impact and projection says to someone, “This person is different. I've got to talk to this person. Maybe this person can help me.”
References: The Aquarian Teacher: KRI International Kundalini Yoga Teacher Training Textbook Level One