机制 is often translated, simply, as: mechanism(s), and often quite ridgidly so.
Especially if we look at definitions of a word like 应急机制
KEY
1 emergency response mechanism(s)
2 contingency mechanism(s)
Take for instance the following sentence:
中国驻俄罗斯大使馆闻讯后立即启动应急机制。
Emergency response mechanisms were started immediately by the Chinese Embassy in Russia after learning of what happened.
Weird.
This is more of a question about semantic fields in English than in Chinese.
From zdic.net
原指机器的构造和工作原理。生物学和医学通过类比借用此词，指生物机体结构组成部分的相互关系，以及其间发生的各种变化过程的物理、化学性质和相互关系。现已广泛应用于自然现象和社会现象，指其内部组织和运行变化的规律。
Originally referred to the structure and operational principles of machines. (The fields of) biology and medicine borrowed this word by analogy to refer to the inter-relationships between the structural components of living organisms, as well as to the various physical and chemical processes therein. It has now been extended in use to natural and social phenomena alike, referring to their laws of internal organisation and operational variation.
I believe that in more recent uses of bureaucratic Chinese, it has extended further to certain social "structures" that perform some kind of operation, something that can be created and implemented at will. This context is rarely one where the English word mechanism is used. Rather, the English language generally prefers to use the word procedure.
中国驻俄罗斯大使馆闻讯后立即启动应急机制。
On learning what had happened, the Chinese Embassy in Russia immediately set up emergency response procedures.
中国驻俄罗斯大使馆闻讯后立即启动应急机制。
An emergency response system was started immediately by the Chinese Embassy in Russia after learning of what happened.
What better ways are there of translating 机制?
system
I think since you've already understand what 机制 means, how to translate it is just a matter of choice of word in the target language.
I'm not a native English speaker, but I think depending on the wording preferences, it could be 'scheme', 'plan', 'system', 'policy', 'procedures'.
Personally, I would translate 应急机制 to 'Emergency Response Scheme' since 'Scheme' means a large-scale systematic plan or arrangement for attaining some particular object or putting a particular idea into effect in Oxford Dictionary. I think it's more appropriate for a social mechanism involving people and consciousness where 'mechanism' is more appropriate for systems involving just components that are inanimate or considered as inanimate.
