U.S. airports used to be the busiest in the world, but passenger air travel in Asia has exploded in recent years, to some extent dwarfing traffic in the west, according to a new report.

Airports Council International (ACI) has released its annual ranking of busiest airports in 2017 and, as has been the trend in recent years, airports in Asia -- particularly China and India --have supplanted U.S. airports in terms of passenger traffic.

Of the top 20 busiest airports for passenger travel ranked by ACI, only five were in the U.S. Nine of the airports were located in Asia, four were in Europe and two were in the Middle East. In 2000, by comparison, 13 U.S. airports were in the top 20 list, followed by five in Europe. In Asia, only Tokyo and Seoul, South Korea, made the list.

Reflecting the growth of the industry in Asia, one of the new airports on the top 20 list in 2017 was Indira Gandhi International Airport in New Delhi, which was 16th on the list with 63.4 million passengers served, up 14 percent from 2016.

"Growing rapidly in a relatively short period of time, India is poised to be one of the largest aviation markets in the world in the years to come," the ACI report stated. "With an astounding population base of over 1.3 billion inhabitants, the move towards a more liberalized aviation market coupled with stronger economic fundamentals has helped to awaken the Bengal tiger to become one of the fastest growing markets in the world."

The report also noted that China was the world's largest contributor to growth in air passenger and cargo volumes, with more than 10 airports that each serve more than 20 million passengers per year. "The growth of Chinese aviation has also boosted international traffic on market segments with other regions such as North America," the report stated.

The U.S., however, continued to hold the top spot in the busiest airport ranking.

The following airports, in ascending order, were identified as the top 10 busiest in the world for passenger traffic:

10. Paris-Charles De Gaulle Airport, France
France's famed airport is the second largest in Europe. It served 69.4 million passengers in 2017, which was a 2.3 percent increase.

 

9. Shanghai Pudong International Airport, China
The traffic at this airport is notable, considering it mainly serves international flights. It served 70 million passengers in 2017, an increase of 6 percent.

 

8. Hong Kong International Airport, China
The airport, which has been in operation since only 1998, acts as a gateway to many mainland China destinations. It is also the site of one of the world's largest passenger terminals. It served 72.6 million passengers in 2017, up 3.4 percent.

 

7. Heathrow Airport, United Kingdom
Located just outside London, Heathrow is the busiest airport in Europe and the second-busiest in the world in terms of international passenger traffic. It served 78 million passengers in 2017 for an increase of 3 percent.

 

6. O'Hare International Airport, Chicago
This is the third-busiest airport in the U.S. The airport is the second-busiest in the world in terms of total takeoffs and landings of all types. In 2017, it served 79.8 million passengers, which was up 2.4 percent from the previous year.

 

5. Los Angeles International Airport, Los Angeles
This is the largest airport on the U.S. West Coast, and also boasts of serving as a hub for the most passenger airlines in the nation. It served 84.5 million passengers last year, up 4.5 percent.

 

4. Tokyo International Airport, Japan
Commonly known as Haneda Airport, the facility is one of two airports serving the Tokyo metropolitan area. It is one of the oldest airports in Asia, having opened in 1931. It served 85.4 million passengers in 2017, up 6.5 percent.

 

3. Dubai International Airport, United Arab Emirates
This airport has gradually been built up into a modern, state-of-the-art facility since it opened in 1960 with a single runway made out of compacted sand. It served 88.2 million passengers in 2017, an increase of 5.5 percent.

 

2. Beijing Capital International Airport, China
The growth of China's busiest airport may be just the start of a major growth surge, according to the ACI report. "The Chinese appetite for air transport services has the potential to add an additional 3 billion passengers by 2040," ACI said. The airport served 95.7 million passengers in 2017, up 1.5 percent.

 

1. Hartsfield-Jackson Atlanta International Airport, Atlanta
This airport continues to be the world's busiest because of its key geographical location, according to the ACI report. "The airport is within a two-hour flight of 80 percent of the United States’ population," the report noted. The airport served 103.9 million passengers in 2017, but it was the only airport in the top 20 that saw a decrease in passenger traffic, with a slight drop of 0.3 percent.