Singapore Airlines flight SQ321

Singapore Airlines flight SQ321

A Boeing airliner flying from London to Singapore encountered turbulence. One man died of an apparent heart attack.

After about 11 hours of flying time, the aircraft sharply dropped from an altitude of about 37,000 feet (11,278 metres) to 31,000 feet (9,449 metres) within five minutes as it crossed the Andaman Sea and neared Thailand, according to FlightRadar 24 data. - Aljazeera

Note that the flight path does not go over Iran or Afghanistan. I suspect the vertical line portion of the flight path is to skirt Kashmir, the site of another Forever War between India and Pakistan.