Inflation has risen fastest in six months to stand at 1.51 per cent.Inflation grew by 0.30 percentage points during the week ended October 17 from 1.21 per cent in the previous week, even as many food items became cheaper.However, on yearly basis, food stuffs remained expensive, turning costlier by 12.85 per cent, with potato prices soaring by 97.73 per cent, onion 45.26 per cent, sugar 45.73 per centand pulses 22.92 per cent.Inflation stood at 10.82 per cent a year ago.