A global ranking of airlines released Monday confirmed that Hartsfield-Jackson International remains the world's busiest airport, despite of a slight decline in passengers.

Airports Council International's ranking of the busiest airports measured by flights and passenger counts kept the Atlanta airport in the No. 1 spot with 103.9 million passengers in 2017, down 0.3 percent from the previous year.

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As Hartsfield-Jackson remains the busiest airport on Earth, passengers traveling during busy periods have encountered lengthy security lines, crowded terminals and congestion on airport roads. The Atlanta airport is in the middle of a $6 billion expansion and modernization program.

Meanwhile, other airports overseas are gaining ground in passenger counts.

In the No. 2 spot for passenger counts is Beijing Capital International Airport, with nearly 95.8 million passengers, up 1.5 percent year-over-year. Dubai International Airport came in at No. 3 in passengers, with 88.2 million passengers, up 5.5 percent.

Tokyo Haneda is at No. 4 for passenger counts, Los Angeles International at No. 5 and Chicago O’Hare at No. 6.

The ranking comes as Atlanta-headquartered airline Delta ranked No. 2 in Wichita State University and Embry-Riddle Aeronautical University's Airline Quality Rating research.

Atlanta is among the airports that had a decline in total flights in 2017, while it remains the world’s busiest for flight counts.

“Though there has been weaker growth in aircraft movements especially in certain North American and European markets following the Great Recession, this is consistent with the move toward consolidated operations and a curbing of capacity by aircraft operators to increase aircraft load factors and improve yields,” according to Airports Council International.