Shanghai Hongqiao International Airport (IATA: SHA, ICAO: ZSSS) is one of two international airports of Shanghai, the largest city by population in China, and a significant airline hub of the country. Hongqiao Airport mainly serves domestic and regional flights, although the airport also serves select international flights (mainly to Seoul–Gimpo, Taipei–Songshan and Tokyo–Haneda). The airport is located near the town of Hongqiao in the outskirts of Changning and Minhang districts, 13 kilometres (8.1 mi) west of downtown, and is closer to the city center than the area's primary international airport, Shanghai–Pudong. Hongqiao Airport is the corporate headquarters and a major hub for China Eastern Airlines, Shanghai Airlines, and Juneyao Air, as well as a major hub for Spring Airlines. In 2016, Hongqiao Airport handled 40,460,135 passengers, making it the 7th busiest airport in China and the 43rd busiest in the world. By the end of 2011, Hongqiao Airport hosted 22 airlines serving 82 scheduled passenger destinations. Shanghai Hongqiao Airport was also certified with the Skytrax 5-Star Airport Rating for facilities, terminal comfort and cleanliness, shopping, food & beverages, and staff service in 2019. Hongqiao Airport served as Shanghai's primary airport until the completion of Pudong International Airport on 1 October 1999, when most international flights were gradually moved to Pudong.