Protests over the NDA's Rafale deal erupted outside the parliament and Congress leader Sonia Gandhi led the opposition in its demand for a probe. Senior Congress leaders were seen holding placards that said, "We demand JPC", "Modi Corruption Exposed", Rafale Cover-Up Out In the Open" etc. "This is the biggest scam of the world. We are demanding the formation of a Joint Parliamentary Committee (JPC) to investigate the Rafale deal," Congress leader Ghulam Nabi Azad said in the Rajya Sabha today.