Mumbai: The BSE Sensex dipped 137 points to a week's low of 18,721, pulled down by blue chips like Infosys on profit booking as investor remained cautious ahead of first corporate quarter results amid weak markets globally.

IT bellwether Infosys, with second heaviest weight on the 30-stock Bombay Stock Exchange index, fell 1.98 per cent ahead of April-June quarter results to be announced on Tuesday.

Besides, Metals and mining stocks continued to slide amid reports that a ministerial panel has approved the draft Mining Bill, proposing that such firms share profits with people affected by their projects and pay royalty to them.

Hindalco, Coal India, Ashapura Minechem, JSW Steel, SAIL, Tata Steel, Nalco, Jindal Steel, Bushan Steel and Welcorp fell 1.13 to 4.41 per cent.

That apart, there was selling pressure on SBI, HDFC Bank, TCS, Bharti Airtel, ICICI Bank, HDFC and Wipro. Realty and banking stocks were down on fears that high inflation and rising interest rates may affect the bottomline of such firms.

Sensex resumed lower and remained in the negative terrain throughout the day, closing 136.65 points or 0.72 per cent down at 18,721.39. Last Friday, it had tumbled by 220.26 points or 1.15 per cent.

Similarly, the broader NSE 50-issue Nifty plunged by 44.55 points or 0.79 per cent to 5,616.10.

"A confluence of factors came together to drag the Indian markets lower for the second day in a row. Chief among them was the nervousness before the all-important results of IT giant Infosys.

Market participants also displayed anxiety ahead of the release of the IIP data and inflation report later this week," said Amar Ambani, Head of Research, IIFL.