Today both indices opened down below the supports (15570/33050). That sets the bearish tone for the day, and as a result, both indices fall further and close in the red.
The bears have the upper hand until the Nifty is trading below the 15530-590 zone. After that, on the downside, 15380 is the support.
The Bank Nifty Index is weaker below the 33050-33200 zone. And to gain the bullish momentum, it needs the close above that. On the downside, 32700 & 32400 are the supports.

Nifty Intraday Gann levels
Nifty bulls need to break & sustain above 15480 to move towards 15520/15570/15630/15700.
On the lower side, the Gann support level is 15380; below that Index can move towards 15340/15290/15230/15160.

Bank Nifty Intraday Gann levels
Bank Nifty bulls need to break & sustain above 33010 to move towards 33160/33360/33610.
On the lower side, the Gann support level is 32700; below that Bank Nifty Index can move towards 32550/32350/32100.
Note: The above levels are for educational purposes. Not a Buy/Sell advice.