New Delhi: India will need to sustain annual economic growth of 8-9% over the next two decades to achieve its ambition of becoming a developed nation by 2047, requiring continued reforms and policy interventions, statistics ministry secretary Saurabh Garg said on Friday.India aims to become a $30 trillion economy by 2047, from its current size of around $4 trillion. The country's gross domestic product (GDP) grew 7.8% in the June quarter, exceeding expectations."We are the fastest-growing economy, and there is no reason we would not have the fastest growth in the foreseeable future," Garg said, adding that the next 20 years represent explosive growth for India.ET BureauEarlier this week, the International Monetary Fund (IMF) raised its growth forecast for India for FY27 to 7%, from 6.4% estimated in July, citing domestic demand and strong services activity.