In a highly volatile session, Indian equity indices failed to hold on to opening gains and ended lower for the fourth straight day on April 18 with Nifty below 22,000.

At close, the Sensex was down 454.69 points or 0.62 percent at 72,488.99, and the Nifty was down 152.05 points or 0.69 percent at 21,995.85.

Despite mixed global cues, the market started in the green, and remained positive in the first half. However, it witnessed extreme volatility in the second half before closing near the day's low.

Biggest losers on the Nifty included Apollo Hospitals, Nestle India, ONGC, Adani Enterprises and Titan Company, while gainers were Bharti Airtel, Power Grid Corporation, Hindalco Industries, Bajaj Auto and LTIMindtree.

Except telecom and media, all other sectoral indices were in the red.

The BSE midcap index shed 0.4 percent, while the smallcap index ended on a flat note.

Among individual stocks, a volume spike of more than 400 percent was seen in Inda Cements, Exide Industries and Power Grid.

A long build-up was seen in Multi Commodity Exchange of India, Bharti Airtel and ICICI Lombard General Insurance Company, while a short build-up was seen in Indraprastha Gas, Apollo Hospitals and Mahanagar Gas.