Question: Which airport that features a skytrain was listed by Skytrax as the World's Best Airport?
Context: Chaudhary Charan Singh International Airport (IATA: LKO, ICAO: VILK) is an airport serving Lucknow, the capital of the Indian state of Uttar Pradesh.  It is situated in Amausi in the city of Lucknow, India and was earlier known as Amausi Airport before being renamed after Chaudhary Charan Singh, the fifth prime minister of India.  It is the 11th busiest airport in India and is also the second busiest and largest in North and Central India after IGI Airport at Delhi.  It handled about 3.97 million passengers in 2016-17.  It was awarded as the second best airport in the world in category of 2-5 million passengers.It is also a focus city for IndiGo. Skytrax (originally known as Inflight Research Services) is a United Kingdom–based consultancy which runs an airline and airport review and ranking site.  Skytrax conducts research for commercial airlines, as well as taking surveys from international travelers to rate cabin staff, airports, airlines, airline lounges, in-flight entertainment, on-board catering, and several other elements of air travel.  Apart from these evaluations, Skytrax has an airline forum where passengers give potential passengers insights and opinions about an airline.  The website also hosts flight reviews, flight checks, and satisfaction surveys.  Skytrax holds an annual World Airline Awards and World Airport Awards, as well as the ranking for airlines and airports. Karonga Airport (IATA: KGJ, ICAO: FWKA) is an airport serving Karonga, a town in the Northern Region of the Republic of Malawi and the best Airport in the Northern part of Malawi. Incheon International Airport (IIA) (IATA: ICN, ICAO: RKSI) (sometimes referred to as Seoul–Incheon International Airport) is the largest airport in South Korea, the primary airport serving the Seoul Capital Area, and one of the largest and busiest airports in the world.  Since 2005, it has been rated the best airport worldwide by Airports Council International every year.  It is also rated as the world's cleanest airport and the world's best international transit airport by Skytrax. Singapore Changi Airport (IATA: SIN, ICAO: WSSS) , or simply Changi Airport, is the primary civilian airport for Singapore, and one of the largest transportation hubs in Southeast Asia.  It is currently rated the World's Best Airport by Skytrax, for the fifth consecutive year (Skytrax's World's Best Airport 2013–2017) and is one of the world's busiest airports by international passenger and cargo traffic.  The airport is located in Changi, at the eastern end of Singapore, approximately 17.2 km northeast from Marina Bay (Singapore's Downtown Core), on a 13 km2 site.  It is operated by Changi Airport Group and it is the home base of Singapore Airlines, Singapore Airlines Cargo, SilkAir, Scoot, Jetstar Asia Airways and BOC Aviation. The Changi Airport Skytrain is an automated people mover that connects Terminals 1, 2 and 3 at Singapore Changi Airport.  Opened in 1990, it was the first driverless and automated system in Asia.  The Changi Airport Skytrain operates from 0500 to 0230 daily.  Traveling on the Skytrain is free and an inter-terminal journey takes approximately four minutes.  All stations are equipped with platform screen doors, are air-conditioned and have plasma displays indicating the arrival time of the next train. Jaipur International Airport (IATA: JAI, ICAO: VIJP) is the primary airport serving Jaipur, the capital of the Indian state of Rajasthan.  Jaipur International Airport has been declared as the World's Best Airport in the category of 2 to 5 million passengers per annum for 2015 according to Airports Council International. Budapest Ferenc Liszt International Airport (Hungarian: "Budapest Liszt Ferenc Nemzetközi Repülőtér" ) (IATA: BUD, ICAO: LHBP) , formerly known as "Budapest Ferihegy International Airport" and still commonly called just Ferihegy, is the international airport serving the Hungarian capital city of Budapest, and by far the largest of the country's four commercial airports.  The airport is located 16 km southeast of the center of Budapest (bordering Pest county) and was renamed in 2011 in honor of the most famous Hungarian composer Franz Liszt (Hungarian Liszt Ferenc) on the occasion of the 200th anniversary of his birth.  The airport won the Skytrax Best Eastern European airport prize three times in a row (2014-2016). Taiwan Taoyuan International Airport (IATA: TPE, ICAO: RCTP) is an international airport serving the capital city of Taipei, Taiwan, and northern parts of the island.  Located about 40 km west of Taipei in Dayuan District, Taoyuan, the airport is Taiwan's largest and busiest airport.  It is one of five Taiwanese airports with regular international flights, and is operated by the Taoyuan International Airport Corporation.  In 2016, it was ranked the best airport for its size in the Asia-Pacific region by Airports Council International. Vancouver International Airport (IATA: YVR, ICAO: CYVR) is located on Sea Island in Richmond, British Columbia, Canada, about 12 km from Downtown Vancouver.  It is the second busiest airport in Canada by aircraft movements (306,799) and passengers (22.3 million), behind Toronto Pearson International Airport.  It has non-stop flights daily to Asia, Europe, Oceania, the United States, Mexico and other airports within Canada.  The airport has won several notable international best airport awards; it won the Skytrax Best North American Airport award in 2007 and 2010 through 2017.  The airport also made the list of top 10 airports in the world for the first time in 2012, rated at 9th (2012), 8th (2013), and 9th (2014) overall.  It is the only North American airport included in the top 10 for 2013 and 2014.  YVR also retains the distinction of Best Canadian Airport in the regional results.  It is a hub for Air Canada and WestJet.  It is also an operating base for Air Transat.  Vancouver International Airport is one of eight Canadian airports that have US Border Preclearance facilities.  It is also one of the few major international airports to have a terminal for scheduled floatplanes.
Answer: Singapore Changi Airport