In a normal situation, the market is in contango for non-perishable commodities to be delivered in the future and that carry storage costs. These costs include storage fees and interest lost on the blocked money, minus the profit from leasing the commodity, if it is the case (e.g. gold). Backwardation is not the normal situation and suggests supply shortages in the spot markets. However, several commodities' markets are often in backwardation, in particular when seasonal aspects are factored in (e.g. perishable commodities). Backwardation rarely occurs in monetary assets like gold and silver, because there is always a large available inventory.
Backwardation in gold and silver is the consequence of interest rate manipulation by the government. Backwardation indicates that people prefer to be holding gold and silver, rather than fiat money (paper money) from a country (dollar, euro, etc.). If paper money were reigning supreme, backwardation in gold and silver would disappear, but this does not seem to be the case now. The gold future contract, cheaper than the spot price, shows that interest rates on gold are more important than fiat money's rates. The more gold and silver go toward backwardation, the more it shows that there is less gold and silver available to trade against dollars or other currencies. There will come a time when there will be no gold or silver available to trade against paper currencies. This will be preceded by a large increase in backwardation, all the way to permanent backwardation. A negative basis indicates a large shortage of available gold for delivery.
Gold backwardation indicated the extent to which gold leases cannot be extinguished by coaxing it from those holding physical gold. Why? Because there is a worry that the gold will not be returned to them.
https://www.goldbroker.com/news/backwardation-contango-gold-silver-market-explanations-466