ICD was started by Seattle radio station KEXP in 2013. The way they see it,
"The enduring power of The Clash and Joe Strummer’s music can be tied directly to the strength of the messages in that music. Again and again, The Clash used music to bring awareness to important issues and highlight the ways that music can bring people together to affect positive change. International Clash Day is about more than just celebrating an awesome band. It’s about the band’s message, which was anti-hate, anti-fear, and promoted unity, tolerance, and activism. That message resonates with listeners and fans to this day. International Clash Day is about celebrating the power of music."
KEXP-produced short documentary on the origins and growth of International Clash Day, through their massive celebration in London for the 40th anniversary of London Calling on Clash Day 2019. Inspiring!