Comments from Sonia Gandhi over the weekend took their toll on the markets. Growing uncertainty in the political alliance between congress and the left lead to volatile swings in the Sensex.After coming very close to 18,000 mark in the opening trade, Sensex slid 660 points in intra-day trade to finally close 282 points in the red. The Nifty also lost more than 100 points closing below 5,100.