The domestic stock markets were battered down, today, in line with continued turmoil in the global bourses. The Sensex at the Bombay Stock Exchange sank a mammoth 807 points, or 3.4 percent, to 22,952. This is the biggest single-day fall of the Sensex in six months, and also a 21-month closing low. The Nifty at the National Stock Exchange tumbled 239 points, to 6,976. Key Asian share markets in Japan and China were closed for a holiday. But the bourses in Hong Kong, South Korea and Singapore were beaten down by between 1.7 percent and 3.9 percent. The story was no better in the European markets, where the bourses in the UK, Germany and France posted big losses of upto 3.1 percent.Global oil prices also slumped. U.S. crude fell 69 cents, to 26.76 dollars a barrel. This is less than a dollar away from an about 13 year low touched last month. Back home, the rupee also dropped sharply, depreciating 45 paise, to an over 29-month low of 68.30 against the dollar. But gold staged yet another rally. In Delhi, gold prices surged 215 rupees, to an 18-month high of 28,800 rupees per ten grams. Overseas, gold rose to a nearly 9-month high of 1,215 dollars an ounce.We asked market expert, Puneet Jain what was the reason behind the slump in the markets.