India should significantly enhance its investment in research and development from the current level of 0.64 per cent to at least 2 per cent of GDP in the next four to five years to strengthen the country's R&D ecosystem, Niti Aayog said on Monday. The Aayog, in a report titled Ease of Doing Research & Development in India - Removing Obstacles, Promoting Enablers, said the government should consider restoring a 5 per cent GST slab for R&D procurement.