These 20 airlines have the cleanest planes in the world

Skytrax has released its annual ranking of the world's airlines.

Among the many prestigious categories is the ranking of carriers according to their cabin cleanliness.

"Passengers rated the standards and quality of cleanliness in the aircraft cabin for airlines," the British consulting firm said. "Cleanliness and presentation of seat areas, tables, carpets, cabin panels and washrooms all contribute toward the final results."

Here's which airlines passengers said had the cleanest planes: