Budget carrier IndiGo on Sunday said that one of its A320neo aircraft that had operated on the Kochi-New Delhi route on Saturday was withdrawn here for a maintenance check to attend to a reported defect. "VT ITK (NEO) operating COK-DEL (Kochi-New Delhi) was alerted with an \u2018oil chip' message on engine #1 post landing at Delhi," the airline said in a statement. "As a part of troubleshooting, aircraft was withdrawn at Delhi. This is a known issue with a prescribed solution. This is not engine failure. Including this aircraft, IndiGo now has seven 'NEOs' grounded."