Thandai is an indian cold drink prepared with a mixture of almonds, fennel seeds, watermelon kernels, rose petals, pepper, poppy seeds, cardamom, saffron, milk and sugar. it is native to india and is often associated with the maha shivaratri and holi or holla mahalla festival. it is most commonly consumed in north india. there are variants of thandai and the most common are badam (almond) thandai and bhang (cannabis) thandai.

Source: Wikipedia