The oldest known event that is still held is Chhath Puja. Because it is a festival of the sun deity, Chhath puja is extremely important at the sunrise and sunset hours. According to the devotee, dawn and sunset are the most important times of the day when a body may safely receive beneficial solar energy without damage. On the scientific side, solar energy has a very low quantity of dangerous UV radiations throughout this time period, making it safe for human bodies.