India probably gathered momentum to hold its ranking as the world's fastest growing large economy in the quarter through March, giving Prime Minister Narendra Modi more to celebrate after completing two years in office last week. Modi swept to power promising to revitalise Asia's third-largest economy and, despite a dearth of private investment and shrinking exports, his policies are having some success as cooling inflation and lower interest rates have boosted consumer demand. A Reuters survey of economists expected data out on Tuesday will show India's gross domestic product grew 7.5 percent year-on-year between January and March, faster than the previous quarter's 7.3 percent. "This 7.5 percent growth, in a global slowdown environment, has a potential to pick up even more," Finance Minister Arun Jaitley said last week in general comments about the trends. India's upbeat outlook contrasts with neighbouring China, where growth slipped to 6.7 i...