Music Composer Gaurav Chatterji best known for his composition of song 'Phoonk Phoonk' from Ginny Weds Sunny, films like 'Aafat-e-Ishq' and many more, now has composed a song and background score for upcoming film 'Jalsa' starring Vidya Balan and Shefali Shah. He talks about the challenges of composing for his upcoming film and how his journey began in Bollywood.