Thandai is commonly prepared during the Festival of Celebration of Lord Shiva and festival of Colors "Holi". It is a very delightful drink full of almonds and spices and best served chilled. I would like to write a little about the festival of Holi, as this drink is usually served quite a lot during this festival.
Holi is a festival of Triumph of good over evil. The ancient story. Hiranyakashipu is the great king of demons, and he had been granted a boon by Lord Brahma, which made it almost impossible for him to be killed. The boon was due to his long penance, after which he had demanded that he not be killed. Consequently, he became arrogant, He demanded that people stop worshiping Gods and start praising him.
According to this belief, Hiranyakashipu's own son, Prahlada, was a devotee of Lord Vishnu. In spite of several threats from Hiranyakashipu, Prahlada continued offering prayers to Lord Vishnu. He was poisoned by Hiranyakashipu, but the poison turned to nectar in his mouth. Enraged, the king decided to punish his son severely and sought his sister Holika’s help. Holika had a boon that fire would never burn her, so the king asked her to sit amid a flaming pyre with Prahlad in her lap so that the child would be devoured by the fire. Prahlad sat with eyes closed, praying to Lord Vishnu and came out unscathed whereas Holika was burnt to ashes. Symbolically on the full moon night of Holi, a bonfire of Holika is made with everyone gathering around it singing and clapping in joy at the destruction of evil. The next day people play with colors.
Holi, is a religious spring festival celebrated by Hindus
A special drink called thandai is prepared (commonly made of almonds, pistachios, rose petals, etc.), sometimes containing bhang (Cannabis ). For wet colors, traditional flowers of Palash are boiled and soaked in water over night to produced yellow colored water, which also had medicinal properties. Unfortunately the commercial aspect of celebration has led to an increase in the use of synthetic colors.