Mumbai: Sensex crashed 349 points, its biggest single-day fall in nearly three weeks, to close at 27,527.22, reflecting pessimism across world markets after a new poll showed Donald Trump nosing ahead of Hillary Clinton in the US presidential race.
The NSE Nifty also succumbed to selling pressure and slipped below the 8,600-mark to finally end at an over three-month low of 8,514, down 112.25 points or 1.30 percent.
This was the lowest closing since 21 July.
An anxiety gripped the market as it opened gap-down and traded in negative bias reflecting pessimism in global markets amid growing concerns over the fate of US presidential elections.
Besides, a caution prevailed among investors as they are keenly awaiting the US Federal Reserve's interest-rate decision.
Vinod Nair, Head of Research, Geojit BNP Paribas Financial Services, said, "Market witnessed intense selling on US election jitters and the FED policy today. The opinion poll suggests a neck to neck competition. Investors believe the volatility will rise until the expectation on US election is really factored in. Fed is likely to maintain the key rates but market is focusing on any signs of rate hike trajectory."
The 30-share index stayed in the negative terrain for the whole day and settled lower by 349.39 points, or 1.25 percent -- its biggest single-day fall since 13 October -- at 27,527.22. Today's closing level was the same as on 17 October when the Sensex had closed at 27,529.97.
The gauge had lost 64.90 points in the past two sessions.
ONGC was the top Sensex loser, skidding 4.10 percent to close at Rs 277.35, followed by Tata Motors, which fell 3.19 percent to Rs 514.
Others such as included SBI, Sun Pharma, RIL, Bharti Airtel, Dr Reddy's, Cipla, TCS, Hero MotoCorp, Maruti Suzuki, Asian Paint and ICICI Bank fell by up to 2.75 percent.
M&M, however, bucked the trend and topped the gainers list by rising 3.54 percent at Rs 1,369.35 after the company posted 1.21 percent increase in total sales in October.
Out of the 30-share Sensex, 26 ended lower today.
Foreign portfolio investors (FPIs) turned net sellers at Rs 123.96 crore yesterday, according to provisional data.
Sector-wise, the BSE oil & gas fell the most by 2.76 percent, followed by realty 2.18 percent, healthcare 2.15 per cent, PSU 2.05 percent and infrastructure 2.02 percent.
The broader markets too fell in line with overall trends with small-cap and mid-cap indices closing lower by 1.84 percent each.
The market breadth turned negative as 1,967 stocks ended lower, 965 finished higher while 110 ruled steady.
Total turnover on BSE amounted to Rs 3,274.15 crore, lower than turnover of Rs 3,318.06 crore registered during the previous trading session.
Globally, Asian shares ended at seven-week low with Japan's Nikkei sinking 1.76 percent and Shanghai Composite plunged 0.63 percent while Hang Seng fell 1.45 percent.
In Europe, most indices retreated, with London's FTSE falling 0.36 percent, France's Paris CAC-30 0.61 percent and Germany's Frankfurt 0.72 percent in their early deals.