I suspect you are looking for phrases like:
not a bit less (than before) [applies to uncountable things]
not corresponds to 不, a bit to 一点 (I don't know Chinese, but in Japanese this is "itten": particle, point, etc), less corresponds to 少. If you want to work in some kind of loose counterpart for 都 to make it more literal: "not a bit less at all than before"; "on the whole, not a bit less than before".
no fewer (than before) [applies to countable things]
at least as much as before [" " uncountable "]
at least as many as before [" " countable "]
Variations are possible, such as "not an iota less than before" (iota = small amount (usually of something uncountable)), "not a drop less water than before" or "not a grain of rice less than before", "not a penny less than before", ...
In mathematics and related technical disciplines, quantities which grow (with respect to some variable) and never diminish are called "monotonically increasing". In a technical field if you want to express that some quantity never decreases (for instance with time), but only gets bigger, you can say that it is "monotonically increasing (with time)".
In English there are various verbs that refer to some sort of decrease with different nuances: erode, dwindle, diminish, decrease, decline, contract, shrink, reduce, ...
These can be negated to indicate the lack of such a decrease: unshrinking supply, undiminishing supply, undwindling stock, unabating effort.