Support - 17,538, 17,400, 17,327
Resistance - 17,770, 17,800, 17,980
The index could suffer another day end closing today below 17,538 (23.6% of Feb low - Apr high), which would open doors for a slide to daily 100-MA support around 17,344 levels.
A break below 23.6% Fibo usually translates into a drop to 38.2% Fibo as well.
On the higher side, a clear break above 18K is needed to signal bearish invalidation.