Benchmark Sensex today slipped from life highs to end sharply lower at 31,710.99 by falling 364 points following a steep plunge in ITC Ltd stocks after the GST Council yesterday hiked tax on cigarettes. Besides, the broader Nifty also cracked below the 9,900- mark. Sentiment was hurt after the GST Council raised the tax on cigarettes to take away an estimated Rs 5,000 crore annual "windfall" manufacturers could have reaped from lower GST rates.