Environment. This can mean whatever surrounds us in a general sense, like in hospital where operations are carried out in a sterile environment, or when we say that children need to grow up in a supportive environment. To give the idea of "životné prostredie" in English, it's usually enough to change "a" to "the" and rely on the context.

USSK's slogan in support of the upcoming Ekotopfilm festival is "Responsible To The Environment" - responsible TO, because the environment is like a superior entity placing this responsibility on the Company (like employees being responsible to their bosses). Responsible FOR is also possible (employees are responsible for the results of their work), but for USSK and the environment it's ambiguous - is the Company responsible for the environment as it is, or as it should be? The interpretation depends on whether we are happy or unhappy with current environmental conditions. Being responsible TO the environment is clear.