Sri Caitanya Mahaprabhu, along with His followers, were performing kirtana. And since that time, kirtana has become inseperable from Ratha Yatra. The kirtana at Ratha Yatra is of equal importance- if not greater- than pulling the chariot of Lord Jagannatha...(HH KKS, Cape Town Ratha Yatra, 24 Jan 2010)