"By the year 2030, India will have the third-largest GDP in the world. China will be No. 1, the US will be No. 2 and India will be third," he said in a speech delivered at the convocation of the 125th course of the NationalDefenceAcademy at Khadakwasla near Pune.
"The challenge of defence forces is to defend and protect the interests of the nation that will have the third-largest GDP in 17 years. When the size (of the economy) increases, the challenge also increases," he said.
Underlining the importance of safeguarding India's access to energy supplies in the context of West Asia, he said, "Our oil import dependence will increase, especially if our growth rate and GDP go up."
Ahluwalia said "the real challenge for us is to redefine the defence challenge we face in a world which will be much more multi-polar."
India, with a GDP of $1.84 trillion, was ranked the 10th-largest economy in 2012, according to the World Bank. The US, at $15.6 trillion, is the largest economy.
India to grow at 5.4% in Q2, says Assocham
How economic crisis doubled Indians' sufferings in recent years
Current account deficit may be 2.5-2.7% this fiscal: Montek
Rupee weakens on month-end dollar demand from oil firms
5 reasons corporates are exiting the new bank licence race