Hi Pradeep,
Theoretically, spot price is supposed to be lower than futures price (asuming a positive cost of carry) and this is evident with their relationshipâ€¦
Future Price = Spot Price + Cost of Carry.
The cost of carry is depended on the interest rate and time.
If market participants expect the cost of carry to increase then the premium (difference between the spot and futures) will increase.
One of the main factors that influences the cost of carry is the interest rates. Any movement in the economy which has an impact on the interest rates will have an impact on cost of carry.
Change in cost carry leads to change in the difference between futures and spot prices.
Besides few more reasons for this variationâ€¦

General demand supply constraints

Corporate actions like dividends, splits, bonus etc.
Thanks for the info,
Does change in Volatility (as in option price) also affect the cost of carry of the future price?
Iâ€™m not sure about this Pradeep.
If you look at the Futures pricing formula i.e F = Se^(rt), there is no input which is based on volatility but in real world this is counter intuitive. There are instances when futures react quicker than spot (mainly driven by volatility) â€¦but over time the effect of this gets evened out.
@Karthik
Sometimes I hear, that nifty futures are at a discount, In that case, will the Cost of carry becomes negative of what?