"Full emergency was declared on Iran Air flight IR 811, after one of its engines caught fire," the unnamed representative from Mumbai's international airport told the Press Trust of India news agency.
All 294 passengers on board the Boeing 747-200 aircraft were safe after the landing on Tuesday night.
An Air India flight en route from Kochi in southern India to Muscat also made an unscheduled stop in Mumbai just over an hour later, the news agency said, quoting an airport official.
The Airbus A320 jet suffered a hydraulic engine failure and landed as a precaution, it said.
