The Sensex is now down 447 points at 18,461.BHEL, ONGC, HDFC Bank and Infosys have plunged around 4.5% each to Rs 2,646, Rs 1,182, Rs 1,469 and Rs 1,630, respectively.Mahindra & Mahindra has shed 4% at Rs 714. Bharti Airtel has slipped 3.6% to Rs 840.ACC, Reliance Communications, Tata Steel and Reliance have slipped over 3% each to Rs 1,005, Rs 687, Rs 808 and Rs 2,652, respectively.Reliance Energy, ICICI Bank, Bajaj Auto and Satyam are the other major losers.ITC has soared 3.3% to Rs 174. Hindustan Unilever and Hindalco have gained 1.4% each at Rs 196 and Rs 205, respectively.SBI has advanced over 1% to Rs 2,186.Out of 2,672 stocks traded so far, 1,867 have declined, 749 have advanced and 56 are unchanged.