It was the third straight session of loss for stocks today as the Sensex took a hit of 216 points to close at a three-week low below the 32,000-mark on growing sense of disquiet following Sebi crackdown against suspected shell companies.
The regulator clamped down on 331 such firms on Monday, directing exchanges to take action against them.
Investors also ran for cover after a flare-up in tension between the US and North Korea over the latter's ballistic missile programme. They fear for the worse as both sides show no signs of backing down, according to traders.
Selling pressure built up following muted June quarter earnings by some companies, they added. It was so strong that all the sectoral indices, led by healthcare and auto, ended in the negative zone.
The Sensex recovered partially before settling down 216.35 points, or 0.68 per cent, at 31,797.84 -- its lowest closing since July 18.
The gauge has now lost 527.57 points in three sessions.
The NSE Nifty also remained under pressure and was down 70.50 points, or 0.71 per cent, to close at 9,908.05. Intra- day, it cracked below the 9,900-mark to touch 9,893.05.
"Global headwinds owing to geo-political tension between North Korea and the US provided more cues to the domestic market, which is already reeling under Sebi's regulatory pressure... Small- and mid-cap underperformed today," said Vinod Nair, Head of Research, Geojit Financial Services.
Overseas, Asian stocks ended lower and European shares dropped in early hours.
In the Sensex pack, Sun Pharma was battered the most, plunging 5.13 per cent to an over four-year low, after its US subsidiary Taro Pharmaceutical Industries reported weak quarterly numbers.
Others to lose ground were Adani Ports (4.12 per cent), along with Cipla, Tata Motors and Bajaj Auto.
But NTPC looked up, climbing 1.25 per cent, followed by ONGC, HDFC and Asian Paints.
Foreign portfolio investors (FPIs) were net buyers of shares worth Rs 1,539.82 crore while domestic institutional investors (DIIs) bought shares worth Rs 798.55 crore yesterday, provisional data showed.
The selling activity accelerated in broader markets, with small-cap index sliding 1.88 per cent and mid-cap 1.66 per cent.
Key indices in Japan, Hong Kong, Singapore, China and Taiwan moved down by up to 1.29 per cent.