You would want to construct (or buy directly) a straddle; premium will be high as they are usually struck ATM.
For lesser premiums you want a strangle. They are struck slightly on either side of ATMs.
However, in India, (I feel), there are not enough long dated index options - going beyond 2 months. With time decay as a factor in options market, buying such instruments turns out to be a gamble.
‘I think within the next month or two Index will fall’ or ‘if the govt wins the ensuing state election markets will rise, but if they drew or did not win, the downside is high’ turn out to be guess work.
Ideally an years worth of liquid options is a good buy; long dated options could be used as a hedge - as their premiums will be less. Long dated OTM options are ideal because they ‘fly’ the most; a good example is a bird; its body or central axis can be thought of as ATM options. When it flaps its wings, the points on the wings, on either side of the body will go up (and down) lesser compared to the tip of the wings which are furthest. With options (Long) the down side is limited hence those OTM options fly.
However, mine is bookish knowledge, I would stand illuminated if there are practitioners in this forum who have found unique ways to overcome this limitation of time and high premium in the Indian context.