At around 9.45 am, Sensex was 1500 points down to trade at 79481.
Nifty dropped 462 points to stand at 24255.
The other broader marketing indices are trading in the negative.
The market nosedived amid fear that the US economy might be facing a recession and escalation of tension in the Middle East.
Data released by the US government on Friday showed unemployment rate rises to 4.3 percent in July.