Follwing yesterday's 717 points fall, the Sensex opened 34 points higher at 18,032, but soon slipped into negative zone owing to follow-up selling in the market. Aggressive selling in mid-noon trades saw the index tumble to a low of 17,226 - down 806 points from the day's open. Selective buying at lower levels helped the index recover some lost ground and eventually end (provisional) the day at 17,595 - down 403 points.