NEW DELHI: After resuming trade at 10.20 am, the BSE benchmarks Sensex and Nifty recovered smartly but were still down 5 per cent each. The pre-open session took place at 10.05 am after the benchmark indices were shut for 45 minutes on breaching the 10 per cent lower circuit limit. At 10.30 am, the BSE Sensex was trading at 31,054.70, down 1,723.44 points or 5.26 per cent.

The NSE barometer Nifty50 was ruling at 9,058.85, down 531.30 points or 5.54 per cent.

The index-based market-wide circuit breaker system applies at three stages of the index movement, either way at 10 per cent, 15 per cent and 20 per cent. Earlier on Friday, the NSE Nifty50 hit its lower circuit at 8,624.05, down 966.10 points or 10.07 per cent.

The BSE Sensex also hit its 10 per cent lower circuit limit at 29,687.52 after falling 3,090.62 points, or 9.43 per cent.

For Sensex, the next circuit (15 per cent) will be at 27,861 level while for Nifty, it will be at 8,152. If any circuit is triggered before 1 pm, the trading will be halted till 1.45 pm.

In case the trading is halted between 1 pm and 2 pm, the trading will be halted for 45 minutes.

Any circuit post 2 pm means the trading will be shut for the day. Not only India, markets in South Korea, Indonesia and Thailand and Philippines also hit their lower circuit limits today. Circuit limits are made to protect investors and brokers from an unwanted surprise moment. Lower or upper circuit limits are an automatic mechanism to stop a freefall or massive surge in a security or an index during trading hours.

Any sudden swing could trigger margin calls, resulting in severe losses for trading.