It was another Black Monday on the Indian stock markets on May 15, as the Sensex -- the benchmark 30-share sensitive index of the Bombay Stock Exchange -- plummeted by a whopping 470 points during intra-day trading. It has since then regained some lost ground.

Heavy selling by institutions and retail investors alike saw the markets plunge from 12,285 points to almost 11,800 points. The Indian markets seemed to mirror the weakness in the other Asian and emerging markets.

Here are some of the biggest falls and gains in the Indian stock market history:

Sensex's biggest falls

April 28, 1992: The Sensex registered a fall of 570 points (12.77 per cent) to close at 3,870, it's biggest ever, following the coming to light of the Harshad Mehta securities scam.

May 17, 2004: Another Monday. Sensex dropped by 565 points, its second biggest fall ever, to close at 4,505. With the NDA out of power and the Left parties, part of the UPA coalition government, flexing their muscle, the Sensex witnessed its biggest intra-day fall of 842

points, twice attracting suspension of trading. At close, however, it regained some of its lost ground.

Sensex's biggest gains

March 24, 1992: The Sensex rises by 426 points (a gain of 13.14 per cent), the highest one-day gain in the history of the Sensex to close at 3,670 following a market-friendly Budget.

May 18, 2004: Sensex gained 371 points, the second highest gain in its history, to close at 4877 following heavy buying.

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