The 5/20 norm was brought in 2004 by the then Civil Aviation Minister Praful Patel to allow Indian private carriers to fly overseas. The rule entailed that an airline based in India will need to have at least five years of experience of flying within the country and 20 aircraft on its fleet before it qualifies to fly overseas.
Ten years later, the government allowed foreign carriers to buy up to 49% in an Indian airline paving the way for Etihad to buy 24% stake in Jet Airways and AirAsia to set up an airline in India in partnership with Tata.
Soon after, the new entrants, who were keen to fly overseas, started lobbying for the 5/20 norm to be relaxed, but the legacy carriers firmly opposed the move fearing competition.
It was in 2016, when the Cabinet approved the National Civil Aviation Policy that the 5/20 norm was replaced with 0/20 allowing airlines to launch international operations with no domestic experience but at least 20 aircraft (or 20% of its entire fleet size whichever is higher) for domestic operations, in a move that was expected to benefit both AirAsia India and Vistara, which is a joint venture between Tata and Singapore Airlines. While Vistara has announced that it will be launching international operations in the second half of 2018 after it recently inducted its 20th aircraft, AirAsia has only 18 planes on its fleet and intends to launch flights on international routes in early 2019.