According to Scary Ideas, these coasters were placed in popular bars throughout Mumbai by the Mumbai Traffic Police, as a reminder of the dangers of driving drunk.
Bloody coasters from Mumbai
The coasters were printed using a special red dye that only appears when the coaster gets wet — so when a drink’s condensation runs down the glass to the coaster, it creates a ring of blood. Yowzers!
This is a pretty good, if unsettling, use — I wonder if we’ll see this special dye used again in a more jovial form at Halloween. [via BoingBoing]