What is 'PAN PAN' call issued by turbulence-hit IndiGo flight?

Srinagar-bound IndiGo flight, which faced a hailstorm on Wednesday, issued a PAN PAN call to Srinagar Air Traffic Control. It's a standard urgency call when a situation requires immediate assistance, but doesn't pose an immediate threat to life, unlike 'MayDay' call which refers to an impending danger to lives of those onboard or to the aircraft itself.