The Airport Council International (ACI) has named the world's best airports in its Airport Service Quality awards (ASQ).

The ASQ awards are based on surveys gauging passenger satisfaction. Airports are also assessed for infrastructure development, with the total number of customers and airlines also taken into account.

The ACI's assessment is considered a key benchmark for customer service in the industry and is believed to be a reliable performance indicator of every airport's service levels.

"This an exciting time for airports. As airports and their operators increasingly accept the positive correlation between passenger satisfaction and airport revenues, we see more and more airports striving to meet, and in some cases exceed, the levels of customer service that their passengers expect from their favoured product and service providers," ACI World Director General Angela Gittens stated on the organisation's website.

"Airports that deliver superior customer service stand apart from the competition and superior customer service remains one of the most important differentiators in the increasingly competitive airport industry," she added.

According to ACI's latest assessment, the top six airports in the world (region-wise) are Moscow's Sheremetyevo International Airport (for Europe), Seoul Incheon International Airport in the South Korean capital (for Asia Pacific), Cape Town Airport in South Africa (for Africa), Cancun International Airport in Mexico (for Latin America-Caribbean), Abu Dhabi International Airport (for the Middle East), and Indianapolis Airport (for North America).

As well as regional toppers, the ACI also lists the best airports in three more categories: by size; by improvements; and by region (fewer than two million passengers).

Check out the complete list here.

Start the slideshow to see the world's top six airports...