I'm curious what you are trying to express here. I have never read/heard "in such environment" and I read a fair amount. Unless there's some technical application, I would use "in such an environment".
After searching on Google, "in such environment" comes up 144,000 times—with many results being similar.
"In such an environment" comes up over 5 million times and seems to be the most popular way of expressing this concept.
The only time I can imagine using "such environment" is when preceded by "no", otherwise, it just sounds wrong to me.
I may be wrong but "in such environment" sounds grammatically incorrect to me.
If you could explain what you're trying to say, it might be easier to help. :) Good luck!