Why do some Indians take an oil bath before sunrise during Diwali. Diwali's traditional oil bath, known as 'Ganga Snan' or 'Abhyanga Snan' or 'Thaila Snan', is usually performed before dawn and symbolises spiritual cleansing and a fresh beginning. Sesame oil is commonly massaged onto the body before a warm water bath. Dr Santosh Pandey, acupuncturist and naturopath, said the ritual may help moisturise skin, improve circulation and relax muscles.