Airports Council International. Delhi Airport was awarded The Best Airport in Central Asia and Best Airport Staff in Central Asia at the Skytrax World Airport Awards 2015. Hindon Domestic Airport in Ghaziabad was inaugurated by Prime Minister Narendra Modi as the second airport for the Delhi-NCR Region on 8 March 2019. A second international airport open for commercial flights has been suggested either by expansion of Meerut Airport or construction of a new airport in Greater Noida. The Taj International Airport project in Jewar has been approved by the Uttar Pradesh government. The Delhi Flying Club, established in 1928 with two de Havilland Moth aircraft named Delhi and Roshanara, was based at Safdarjung Airport which started operations in 1929, when it was the Delhi's only airport and the second in India. The airport functioned until 2001; however, in January 2002 the government closed the airport for flying activities because of security concerns following the New York attacks in September 2001. Since then, the club only carries out aircraft maintenance courses and is used for helicopter rides to Indira Gandhi International Airport for VIP including the president and the prime minister. Road Delhi has the highest road density of 2103 km/100 km2 in India. It is connected to other parts of India by five National Highways: NH 1, NH 2, NH 8, NH 10 and NH 24. The Delhi–Mumbai and Delhi–Kolkata prongs of the Golden Quadrilateral start from the city. The city's road network is maintained by MCD, NDMC, Delhi Cantonment Board, Public Works Department (PWD) and Delhi Development Authority. Buses are the most popular means of road transport catering to about 60% of Delhi's total demand. Delhi has one of India's largest bus transport systems. In 1998, the Supreme Court of India ruled that all public transport vehicles in Delhi must be fuelled by compressed natural gas (CNG) to tackle increasing vehicular pollution. The state-owned Delhi Transport Corporation (DTC) is a major bus service provider which operates the world's largest fleet of CNG-fuelled buses. In addition, cluster scheme buses are operated by Delhi Integrated Multi-Modal Transit System (DIMTS) with the participation of private concessionaires and DTC. In December 2017, the DTC and cluster buses carried over 4.19 million passengers per day. Kashmiri Gate ISBT, Anand Vihar ISBT and Sarai Kale Khan ISBT are the main bus terminals for outstation buses plying to neighbouring states. Delhi's rapid rate of economic development