Mumbai: The Bombay Stock Exchange benchmark Sensex today plunged by 319.21 points at mid-session as banking stocks continued to fall for the second day in a row.

The sensex, which had temporarily returned to positive terrirtory after a weak opening, tanked further in the afternoon trade taking its two-day fall to over 700 points in intra-day trading.

The key index was hovering just over the 13,000 level, while NSE's Nifty was trading below the crucial support level of 3,800 points.

Nifty was trading 109 points down at 3740.50, while Sensex was at 13,080.

Almost all the segment indices were in red but banking stocks suffered the most due to the Reserve Bank's move to hike CRR of banks by 50 basis points.