India's economy rose 8.4 per cent in the October-December period, the fastest pace seen in six quarters and beating all estimates, partly helped by a surge in manufacturing activity, according to data released by the government on Thursday. The growth rate was much faster than economists' forecasts of 6.6 per cent as seen in a Reuters poll, and higher than the revised growth of 8.1 per cent in the previous quarter. The manufacturing sector, which for the past decade has accounted for just 17 per cent of Asia's third-largest economy, expanded 11.6 per cent year-on-year in the December quarter, compared with a revised 14.4 per cent in the previous three months.