, ECS2606
ASSIGNMENT 1 SEMESTER 2
2026
DUE 14 AUGUST 2026
Question 1 - Environmental Economics Assignment: River Pollution in Gauteng
1.1 Market Efficiency vs. Social Efficiency
Explanation
Market Efficiency occurs when the private costs and benefits of production and consumption are
balanced in competitive markets. At market equilibrium, the price reflects only the private marginal
costs (PMC) borne by producers and the private marginal benefits (PMB) received by consumers.
Market efficiency is achieved when:
Quantity is determined by supply and demand
Producers minimize their private costs
Consumers maximize their private utility
Social Efficiency occurs when all costs and benefits are accounted for, including externalities (costs
or benefits affecting third parties). Social efficiency requires that:
Marginal Social Cost (MSC) = Private Marginal Cost (PMC) + Marginal External Cost (MEC)
Marginal Social Benefit (MSB) = Private Marginal Benefit (PMB) + Marginal External Benefit
(MEB)
Social efficiency is achieved where MSC = MSB
The Difference
The key distinction is that market efficiency ignores externalities, while social efficiency includes
them. When negative externalities (like pollution) exist, the market produces too much of the good
at too low a price, leading to environmental degradation.
ASSIGNMENT 1 SEMESTER 2
2026
DUE 14 AUGUST 2026
Question 1 - Environmental Economics Assignment: River Pollution in Gauteng
1.1 Market Efficiency vs. Social Efficiency
Explanation
Market Efficiency occurs when the private costs and benefits of production and consumption are
balanced in competitive markets. At market equilibrium, the price reflects only the private marginal
costs (PMC) borne by producers and the private marginal benefits (PMB) received by consumers.
Market efficiency is achieved when:
Quantity is determined by supply and demand
Producers minimize their private costs
Consumers maximize their private utility
Social Efficiency occurs when all costs and benefits are accounted for, including externalities (costs
or benefits affecting third parties). Social efficiency requires that:
Marginal Social Cost (MSC) = Private Marginal Cost (PMC) + Marginal External Cost (MEC)
Marginal Social Benefit (MSB) = Private Marginal Benefit (PMB) + Marginal External Benefit
(MEB)
Social efficiency is achieved where MSC = MSB
The Difference
The key distinction is that market efficiency ignores externalities, while social efficiency includes
them. When negative externalities (like pollution) exist, the market produces too much of the good
at too low a price, leading to environmental degradation.
