The month of Magh is observed as Kalpvas where for one month people from all over gather, do sun worship (vitamin D), eat sesame (high in calcium) and do tulsi or basil pooja (high fertility and high in calcium). The significance behind is to accrue one year’s vitamin D quota. To make enough vitamin D we need to expose 40% of the body for at least 40 minutes at a stretch for 40 days in a year (Formula of 40).