The phrase "a time when concerns" is correct and usable in written English.
It can be used to refer to a specific period or situation in which certain worries or issues were present.
Example: "There was a time when concerns about climate change were often dismissed as exaggerated."
Alternatives: "an era of worries" or "a period of apprehensions".
He came at a time when concerns are growing over Iraq's role in the crisis in Syria, and when the United States' influence in Iraq has been dwindling.
Families of Freedom 2 makes its debut at a time when concerns about the long-term needs of tens of thousands of victims are gaining momentum.
It comes at a time when concerns are growing in the semi-autonomous Chinese city that Beijing is tightening its grip.
The movie is landing at a time when concerns about animal welfare are growing in importance to Americans, companies and politicians.
Longfield's report made difficult reading for the government at a time when concerns over the health service have reached a critical level.
The report, Can Less Work Be More Fair?, comes at a time when concerns about jobs being displaced by robots and other forms of technology are heightened.
It makes little sense to relax rules involving a potential bomb fuel at a time when concern about terrorism remains high, he said.
He asserted the validity of the two testaments at a time when concern for the unity and the difference between the two parts of the Bible was developing.
Sometimes this has been controversial, such as his willingness to work with De Beers at a time when concern about "conflict diamonds" was at its height.
The alliances were announced at a time when concern in Washington about the power of the big airlines to dominate major airports was already on the rise.
Wind power producers, he says, can't keep pace with demand at a time when concern about global warming is driving governments to promote greener electricity.
