Fishing is a beautiful thing. Some cast nets into the water, some sling a fishing rod with a bait attached. But fishing in some states in India is way different (and more brutal?) than anywhere else.
This battery is used to generate the electricity needed to kill the fish. Reddit
That current could be strong enough to kill a man, as has been documented by Ajay Balachandran, Krishnan B., and Liza John in their case study on similar fishing practice in Kerala.