The BSE benchmark Sensex on Tuesday tanked over 325 points to dip below 18,000 level in the early trade on sustained selling, extending losses for the third straight day, as rupee plunged to fresh lows amid a weakening trend overseas.

The 30-share index slipped below 18,000 mark by plunging 325.64 points, or 1.78 per cent, to 17,981.88.

All sectoral indices led by financials and realty trading in negative territory with fall up to 3.08 per cent.

Sensex had lost over 1,060 points in the previous two sessions.

Similarly, the wide-based National Stock Exchange index Nifty slipped below 5,400 points mark by falling 91.75 points, or 1.69 per cent, to 5,323.

Brokers said sentiments remained extremely bearish on heavy selling on free-fall in the rupee’s value that hit another record low of 63.75 against the dollar, and a weakening trend in the global market as investors bet that the US Fed will soon announce a wind-down of its massive bond-buying programme.

In the Asian region, Hong Kong’s Hang Seng index was down 0.30 per cent, while Japan’s Nikkei Index shed 0.53 per cent in the morning trade on Tuesday.

The US Dow Jones Industrial Average ended 0.47 per cent lower in Monday’s trade.