In economics, an agent's preferences are said to be weakly monotonic if, given a consumption bundle
An agent's preferences are said to be strongly monotonic if, given a consumption bundle
, the agent prefers all consumption bundles
This definition defines monotonic increasing preferences.
Monotonic decreasing preferences can often be defined to be compatible with this definition.
In this case, the agent's preferences for lack of pollution are monotonic increasing.
Much of consumer theory relies on a weaker assumption, local nonsatiation.
If an agent has monotone preferences which means the marginal rate of substitution of the agent's indifference curve is positive.