The BSE Sensex dropped 304.59 points, or 1.48 per cent to end at 20,209.26, the weakest level since 20,217.39 on November 22, 2013. This was the sixth drop in seven sessions.
On Friday, it gained 15.60 points while in the previous 5 days the index plunged 875.41 points.
Infosys, ICICI Bank and Tata Motors led the 25 losers in the 30-share Sensex today. The biggest laggards were Hindalco Industries and Tata Steel. Sun Pharmaceuticals Industries, Dr Reddys Laboratories and Cipla gained.
The 50-share NSE Nifty intra-day dipped below 6,000 level. It ended at 6,001.80, down 87.70 points, or 1.44 per cent.
Brokers said the foreign investors offloaded their positions after reports of slowing manufacturing in China, the world's largest user of metals. Investors seemed to ignore data showing that India's manufacturing sector in January expanded at the strongest pace in the past 10 months.
They said the fund managers were also worried over the US Federal Reserve's decision to further cut monetary stimulus by USD 10 billion per month will tighten capital inflows into emerging markets like India.
Overall, 11 of the 12 sectors ended in the red. Only healthcare stocks, considered defensive bets, saw respite.
Sectorally, the BSE Metal sector index suffered the most by losing 3.06 per cent,