Mumbai, Oct. 17 -- The Federal Reserve Bank of Philadelphia released a report on Thursday showing a substantial pullback by its reading on regional manufacturing activity in the month of October.

The Philly Fed said its diffusion index for current general activity plummeted to a negative 12.8 in October after spiking to a positive 23.2 in September, with a negative reading indicating contraction.

With the much bigger than expected decrease, the Philly Fed index tumbled to its lowest level since hitting a negative 26.4 in April.

The report said 25 percent of firms reported decreases in general activity in October, up from 17 percent in September, while 12 percent reported increases in general activity in October, down from 40 percent in S...