Equity benchmark indices edged lower during early hours on Thursday due to weak global cues after the International Monetary Fund forecast the global output to shrink by 4.9 per cent this year.
A surge in coronavirus cases worldwide also spooked investor confidence.
The IMF predicted the Indian economy to contract by 4.5 per cent following a longer COVID-19 lockdown period and slower recovery than anticipated in April.
At 10:15 am, the BSE S-P Sensex dropped by 166 points or 0.48 per cent at 34,703 while the Nifty 50 slipped by 34 points or 0.33 per cent at 10,271.
Sectoral indices at the National Stock Exchange were mixed with Nifty PSU bank down by 1.2 per cent, private bank by 1.1 per cent and IT by 0.9 per cent.
Among stocks, Bharti Infratel was down by 4.7 per cent to Rs 222.05 following the board's decision to extend deadline for merger with Indus Towers by over two months till August 31.