Mumbai: Falling for the second day in a row, the benchmark Sensex on Wednesday closed below 18,000 level after losing another 169 points due to sustained selling, mainly in L&T and RIL, on persisting concerns over economic growth amid weak global cues.

The Bombay Stock Exchange 30-share barometer resumed sharply lower on weak Asian trends and remained in negative terrain throughout the day, before settling lower 169.34 points at 17,940.55, a level not seen since June 23.

On Wednesday, it had tumbled by 204.44 points.

Brokers said profit-booking in blue-chips Larsen & Toubro (L&T), ICICI Bank, Reliance Industries (RIL), TCS, Infosys and Bharti Airtel pulled the Sensex down.

Telecom major Bharti Airtel slipped over 1 per cent after the company reported nearly 28 per cent decline in Q1 profit.

"The weakness persisted on account of slowdown in the global economy and disappointing results by Indian corporates. Asian markets declined nearly 1-2 per cent each," Motilal Oswal Securities Associate Vice President Parag Doctor said.

The broad-based National Stock Exchange's Nifty tumbled by 51.75 points or 0.95 per cent to 5,404.80. It touched an intra-day low of 5,378.85.

Analysts said operators as well as retail investors preferred to book profits on concerns over the economic growth after Prime Minister's Economic Advisory panel lowered the GDP growth forecast to 8.2 per cent for this fiscal.

"The undercurrent remains fragile amid persistent declines for equity markets around the world. Investors are jittery about the health of the global economy amid mounting concerns about the sovereign debt problems in the US and eurozone," Doctor said. Engineering giant L&T was the top loser among the index stocks falling by 4.33 per cent. Among other major losers, ICICI Bank fell by 1.97 per cent, Reliance Industries by 1.19 per cent and Tata Motors by 3 per cent.

TCS declined by 1.86 per cent and Infosys Tech by 0.76 per cent on weak economic concerns in western markets, while realty major DLF lost 2.15 per cent on weak quarterly results.

Eleven out of 13 sectoral indices ended in the red. The BSE-Consumer Goods slumped by 2.65 per cent, BSE-Auto by 1.45 pct, BSE-HC by 1.02 per cent and BSE-IT by 1 per cent.

Recent economic statistics from the US have been pretty downbeat, fueling fears of an accelerated slowdown in the world's largest economy. Risk aversion is on the rise, with gold hitting new record high and investors flocking to other safe havens like bonds and Swiss francs, Doctor said.

IIFL Head of Research (India Private Clients) Amar Ambani, however, said, "Hopefully, we will see a rebound after a two-day selloff. The European markets had already recovered,and US stock futures were also positive. The monthly US jobs data on Friday will be an important event to watch out for."

Asian shares fell heavily across the board. The key benchmark indices in China, Hong Kong, Japan, Singapore, South Korea and Taiwan fell between 0.03 per cent and 2.59 per cent.

European markets too were trading lower in mid-session deals. The CAC was down by 0.51 per cent, the DAX by 0.82 per cent and FTSE by 1.06 per cent.

The total market breadth at BSE was negative as 1,706 counters ended with losses, as against 1,160 that closed with gains. The turnover improved further to Rs 2,576.76 crore from Rs 2,451.52 crore on Tuesday.