The Aircraft Accident Investigation Bureau (AAIB) has recommended that the Directorate General of Civil Aviation (DGCA) inspect airlines' safety management systems following a serious airprox incident involving two IndiGo planes on November 17, 2023. The incident occurred in Delhi airspace between an A321 and an A320. The AAIB report cited non-adherence to Standard Operating Procedures by one flight crew and the airline's delayed action on prior SID-related occurrences as probable and contributing factors, respectively.