Elasticity refers to how strongly the quantity demanded or supplied responds to changes in price. When both demand and supply are elastic, small price changes result in significant shifts in the quantities traded. A price ceiling, which is a government-imposed limit on how high a price can be, is set below the equilibrium price. While intended to make essential goods affordable, this intervention often disrupts the natural equilibrium, particularly in markets with elastic demand and supply, leading to inefficiencies.

In markets with elastic demand, a price ceiling lowers prices below equilibrium, causing consumers to demand more of the good or service. Simultaneously, the reduced price discourages producers from supplying the same quantity, as their profits shrink. This disparity results in a shortage, where the quantity demanded exceeds the quantity supplied.

Deadweight loss refers to the loss of potential trades and economic value that occurs when market transactions are prevented by external interventions, such as a price ceiling. In inelastic markets, where both consumers and producers react sharply to price changes, the deadweight loss is more pronounced. Buyers who would have purchased at a higher equilibrium price and sellers willing to supply at that price are both excluded from the market. As a result, the total number of mutually beneficial trades decreases, reducing overall market efficiency.