The Indian Directorate General of Civil Aviation (DGCA) has ordered IndiGo Airlines (6E, Delhi Int'l) to ground one A320-200neo with unmodified Pratt & Whitney PW1127G-JM engines per every unit put back into service after the modifications, the Press Trust of India (PTI) has reported.

The order was issued to prevent large-scale cancellations after January 31. IndiGo Airlines was previously given until the end of January to modify engines on all ninety A320neo and seven A321-200neo by that day but the DGCA said it was worried that it will not happen.

"[The current rate of modifications does not] instil enough confidence with regard to the timely completion of the said task," an unnamed official said. "The grounded aircraft can be allowed a fresh schedule once its PW engines are replaced."

Effectively, the airline will not be able to open new routes until it modifies the engines of all aircraft.

"If left unaddressed, we may find ourselves in a situation in which we remain saddled with large number of aircraft with unmodified engines and operating on a schedule approved by us. We are left with the only option i.e. to ground them on January 31, 2020," the official added.

It is unclear how many of IndiGo Airlines' ninety-seven A320neo Family aircraft have already had their engines modified. The carrier did not respond to ch-aviation's request for more information.

Besides the A320neo and A321neo, IndiGo Airlines also operates 126 A320-200s and twenty-three ATR72-600s.

In separate news, IndiGo's independent director Anupam Khanna has petitioned the Maryland District Court to drop a subpoena issued against him in relation to a case filed by the airline's founder Rahul Bhatia against co-founder Rakesh Gangwal. The court sought to extract Khanna's correspondence with Gangwal. However, Khanna argued that the US court had no jurisdiction given that the original case is a private law dispute in front of the Indian branch of the London Court of International Arbitration.