The Sensex at the Bombay Stock Exchange rallied 121 points, or 0.7 per cent, to close with the biggest annual gain in 18 years, at 17,465, on Thursday. The Nifty at the National Stock Exchange rose 32 points, or 0.6 per cent, to 5,201.Stock markets in China, Hong Kong and Singapore rose between 0.5 per cent and 2 per cent.