Today's has done monthly expiry in Nifty/Banknifty both u can see that today market has volatile. I think next month banknifty breaks it's all time high & showing it's strength.
As per chart analysis u can see that one new trendline appear & act like support, So market will come to test this trendline & then market get ready for upside also for upside market planned to hits sellers stoploss.