Mumbai, Jan 23 : After a gap up opening of 145 points on the back of positive global cues, Nifty could not hold on to the gains and turned south on Tuesday. Nifty nosedived by more than 1.5 per cent to close at 21,238, said Devarsh Vakil, Deputy Head of Retail Research at HDFC Securities. Nifty Midcap 100 and Smallcap 100 Indices plunged by 3.11 per cent and 2.87 per cent, respectively. Declining shares outnumbered the advancing shares as the advance decline ratio stood at 0.32 on BSE, lowest since December 20, 2023. All the sectoral Indices ended in the red except Nifty Pharma. Among them, Nifty Media, Nifty Reality and Nifty Metal fell the most, Vakil said. By breaking the previous swing low of 21,285, Nifty has conformed lower top and lower bottom formation on the daily chart, which indicates bearish trend reversal. Nifty is now headed towards the next support zone of 20,850-20,900. On the upside, 21,750 has become ceiling in the Nifty for the short term, Vakil said. Nagaraj Shetti, Senior Technical Research Analyst at HDFC Securities, said the short-term trend of Nifty is down and one may expect more weakness in the short term. The next important support zone to be watched is around 20,950-20,850 levels, which are coinciding with supports of previous up gap of December 14, swing low of December 21 and also 38.2 per cent Fibonacci retracement of October 23 bottom to January 24 top. Immediate resistance is at 21,400 levels. /IANS