Bhang is cannabis or marijuana. In India its called Bhang, Charas and Ganja. The ganja is the leaves of the marijuana plant, the charas is the resin while ganja is the leaves and flowers of the plant. The most potent is the charas or the resin which is smoked combined with tobacco something which is called chillum. You'll often find sadhus or holy men smoking the chillum.

Most people who do not use marijuana however do use the bhang on special festivals such as Mahashivratri or the festival of Holi. Bhang lassi is often drank on these days and there are many shops selling bhang lassi in Varanasi in government approved shops or even on the streets. Ideally there are supposed to be government approved bhang shops but most vendors sell bhang without license. The authorities however do no make any attempts to curb the practice for cultural reasons.