As those operations are often in places that impose tough environmental restrictions on industry, cleaner methods are needed.

由于这些操作通常在对工业施加严格环境限制的地方进行，因此需要更清洁的方法。

On the other side, universities like UC Berkeley say environmental restrictions in California make it difficult for them to build new housing for students.

另一方面，加州大学伯克利分校等大学表示，加州的环境限制措施使他们难以为学生建造新的住房。

" The last couple of years, dry years, coupled with severe environmental restrictions, has now presented us with a zero allocation year, " said Errotabere.

“过去几年干旱，同时还有严格的环境限制，我们每年分配的水是零。”