Nagvekar has won a $25,000 college scholarship, lifetime membership in the National Geographic Society and a trip for two to the Galapagos on an expedition aboard the National Geographic Endeavour. Second prizewinner, Jain received $15,000 college scholarship.
Thirteen-year-old seventh-grader Mahadevan, who took third place, got $10,000 college scholarship, while 14-year-old eighth-grader Ranga, who bagged fourth place, took $1,000, an official release said.
The winning question was: Name the Bavarian city located on the Danube River that was the legislative seat of the Holy Roman Empire from 1663 to 1806? Nagvekar won by correctly answering as "Regensburg".
"It was a guess, a 50-50 chance. It just happened to be a good guess," Nagvekar said after the competition.
US President Barack Obama asked one question this year via video, quizzing the young contenders on their knowledge of recent events.
Obama asked which Asian capital city on the Han River hosted a gathering of world leaders in March for a Nuclear Security Summit. The answer to which was "Seoul".
Obama said that studying geography is "about more than just memorising places on a map".