Four domestic airlines – Indigo, Air India, Spice Jet and Go Air announced a ban on stand-up comedian Kunal Kamra after he heckled Arnab Goswami on Indigo’s Lucknow-bound flight from Mumbai. While Indigo said it was putting Kamra on a no-fly list for six months, other airlines said they had put him under an indefinite suspension. What are the rules and regulations that airlines have to follow while placing a passenger on a no-fly list?