Bonalu is a Hindu festival celebrated mostly in Hyderabad. The festival is meant to give thanks to the goddess Mahakali (महाकाली), who is also called Kali (काली).
Some of the women are said to be in a trance, and these women lay a pot on top of their heads on their way to the temple. The tranced women are said to possess the spirit of the Goddess. The Goddess is often described as an aggressive figure. It’s believed that the tranced women have personified the spirit of the Goddess.
When the tranced women reach the temple (photo below), people pour water on their feet. It’s said that pouring water will pacify the Goddess