The 30-share index opened higher at 20,326.66 and firmed up further to 20,533.28 before quoting 20,516.50 points at 1030 hours. It gained 299.39 points, or 1.48 per cent, from the previous close.
There was buying in banking, capital goods, realty, FMCG, metal and PSU sector stocks.
The 50-share CNX Nifty moved up 91.20 points, or 1.52 per cent, to 6,086.65 at 1030 hours.
The major gainers were ICICI Bank (3.52 pc), Larsen & Toubro (2.8 pc), Sesa Sterlite (2.32 pc), HDFC Bank (2.30 pc), Hero MotoCorp (2.23 pc), Tata Motors (2.09 pc) and ITC (2.01 pc).
Iran reached a deal with world powers in Geneva yesterday to slow it's controversial nuclear programme in return for about USD 7 billion in sanctions relief.