The Sensex dropped to a low of 15,745 in late-noon trades and finally ended with losses of 286 points or 1.7% at 15,865. Nifty ended down 77 points at 4,772.
A weak opening of European bourses weighed on sentiments.
Asian markets continued to slip amid fears of Europe's debt troubles.
The Nikkei slipped 1% to 8,456. Hang Seng was down 3.4%, while Seoul and Straits Times also posted similar losses.
Back in India, banking stocks fell with the BSE bankex dropping 3% to 10,219.
State Bank of India's (SBI) financial strength rating has been downgraded by Moody's Investors Service on the banking entity's capital situation and deteriorating asset quality.
SBI's BFSR has been downgraded from D+ from C-. The downgrade comes a day after Fitch Ratings cut its estimate for India's economic growth from 7.7% to 7.5% for 2011-2012.
For 2012-13, it has estimated India's gross domestic product growth at 8%, down from previous estimate of 8.2%. This is attributed to weak growth forecasts for all major advanced economies.
"SBI is a government-backed
Zurich: Where the world's richest come for banking
Why Moody's downgraded SBI
BSE gets Sebi approval for SME Exchange
Bengal government warns banks
Chidambaram reviews Mumbai's security situation