The 50 index witnessed a jittery opening ahead of the budget day; however, it trended with a positive bias after marking an intraday low of 21448 within the opening minutes. The day's closing came on a stronger foot with a relatively higher volume. The 21500PE strikes added the highest open interest on the derivative front, indicating immediate support. On the higher side, 21800 will continue to act as immediate and stiff resistance and a closing above this zone will attract further bullish momentum.