They dye the clothes right there in pits that have been in use for 300 years. Many of the pits have fallen into disrepair and are full of garbage, but there are still several that were full of dye.
Nigeria's 500-year-old 'dye pits' survive despite threats
Kofar Mata Dyeing Pits — The tie and dye process of the old north
5 centuries in business: Nigeria's ancient dye pits
Dye pits and traditional dyeing activities in Kofar Mata, Kano
Dye pits kano nigeria hi-res stock photography and images - Alamy
KOFAR DYE PITS: THE BEAUTY OF KANO
Dying cloth at Kano's dye pits, PRI's The World
Dyeing pits, Kano, Kano state, Nigeria, West Africa, Africa Stock
This is where tie dye was invented in Nigeria I had no idea that
The 'dying' dye pits of Kano - Tribune Online
5 centuries in business: Nigeria's ancient dye pits