Nifty is largely in a downward channel and the downward slide is likely to continue as market outlook is bearish. the critical levels are 17550/17430. if gap-up opening or flat opening and upmove and sustain above 17550 on 15 min chart, then a small upside move till 17650 is on cards. however if the gap-down opening or flat open and down movement, short can be entered into below 17430 with stoploss at 17450. downside target will be 17400 / 17355. sell on rise should be the way to go.