The correct answer is Chhatrapati Shivaji Maharaj International Airport.

• Chhatrapati Shivaji Maharaj International Airport is in Mumbai by its known as Sahar International Airport. Chhatrapati Shivaji International Airport is the second busiest airport in the country after Delhi.
• The Airport has three operating terminal spread over the total land area of 750 hectares Chhatrapati Shivaji International Airport. it is opened in 1942 in  Mumbai,  Maharashtra.

• Indira Gandhi International Airport is located in Delhi. Indira Gandhi International Airport is the busiest airport in India in the term of 5 passengers traffic.It was the 12th busiest airport in the world and 6th busiest airport in Asia by passenger traffic handling nearly seventy million passengers.
• Rajiv Gandhi International Airport is located in Hyderabad. Rajiv Gandhi International Airport  is also busiest airport by passenger traffic in India. Rajiv Gandhi International Airport has been awarded in multiple categories such as world's top 3 airports by askew Bing in just one of them.
• Anna International Airport is located in Chennai,Tamil Nadu. It is also called as Chennai International Airport. Chennai International Airport is the third busiest in international traffic and cargo capacity in the country behind New Delhi and Mumbai.