I understand the meaning of the word sufficient like defined in Merriam-Webster:
sufficient = enough to meet the needs of a situation or a proposed end
So mathematically said:
not less than the needed minimum
Is there an "upside-down counterpart"?
not more than the needed maximum
It should be of the same style as sufficient or enough, expressing the same concept (being within limits and not being under the maximum).
Let's have an example of a chemical reaction. In order the reaction can start, you need at least 5% concentration of a given substance. So if the concentration is 6%, we say that the concentration is sufficient. (Also suggesting that no more concentration increasing is needed.)
However, what if the requirement is that in order the reaction can start, the concentration of the given substance should be at most 95%. So if we have 94%, the concentration is ...? Sufficient here sounds funny...
Analogically, it should also bear the notion of no more concentration decreasing is needed.
I am searching for a single word in the same common style as enough of sufficient, not for a mathematical expression.
N.B.: I do not mean the same as in the related question Can "sufficient" be used in a negative sense?