It earned the label by meeting standards developed by the Indian Green Building Council, the local chapter of U.S. Green Building Council, which created LEED standards. (Here I must give a shout-out to my hometown San Francisco International Airport, whose Terminal 2 also won gold certification, soon after Delhi did.) Rajiv Gandhi International Airport in Hyderabad also won a LEED-Silver rating.
FORBES: India's Airport Boom Embraces Green Building