Answer a question about this article:
Indira Gandhi International Airport, situated to the southwest of Delhi, is the main gateway for the city's domestic and international civilian air traffic. In 2012-13, the airport was used by more than 35 million passengers, making it one of the busiest airports in South Asia. Terminal 3, which cost 96.8 billion (US$1.4 billion) to construct between 2007 and 2010, handles an additional 37 million passengers annually.
Approximately how many passengers used Indira Gandhi Airport from 2012-2013?
35 million