Gurgaon-based IndiGo, which recently got listed on the bourses, had in October this year said it would take delivery of 10 fuel-efficient A320neos by March next year.
"The type certification of the new design of the six Airbus 320neos are expected to be completed by December 10", a DGCA official said.
Certification from the Directorate General of Civil Aviation (DGCA) is mandatory prior to induction of any type of new aircraft in the fleet.
European aircraft maker Airbus claims these new type of aircraft burns 10-15 per cent less fuel than the existing versions.
Significantly, 2016 has been termed as the year of A320 neos for the Indian carriers as apart from IndiGo, two other budget airlines GoAir and Vistara are also scheduled to induct these planes in their fleet.
Currently, IndiGo has a fleet of 98 aircraft and about 75 of them are on operating lease -- a business model which has helped it lower costs.