"one area on which" is correct and usable in written English.
It is a phrase commonly used for introducing a topic or point of discussion in a sentence. You can use it when you want to draw attention to a specific topic or aspect within a broader context. For example: One area on which we need to focus our attention is the education system.
Violence against women is one area on which she intends to concentrate.
One area on which Dawkins eventually capitulated was retaining an archive of posts.
One area on which Henn na Hotel still relies on humans is security.
"There is one area on which I believe we haven't focused on enough – how work is good for your health.
One area on which he happily elaborates is why Minnesota has more effective medical care than Massachusetts, which he says has expanded access at the price of out-of-control costs.
And yet, if Larsson were still around, I feel sure there's at least one area on which we'd agree (two if you count on the importance of training female Eritrean People's Liberation Front guerrillas in the use of grenade launchers).
Despite these deep-seated differences, there is one crucial area on which the Europeans ought to be able to agree.
So the opportunity for the investor is that it's opened up more alternatives, more possibilities, shall we say, for investors to make money rather then focusing on just one area, which for many is technology.
The thin actor, who bore a certain resemblance to a young Lucian Freud, played a writer who could not get on with his work; one area in which he could exercise some control, though, was in the gambling hall, where he had a job as a card dealer.
Second, selection bias may have occurred because we based our study on a cohort from one area hospital, which treated pregnant women in Sapporo and the surrounding areas.
However for the third time Cooke was unable to convert, one area in which Hull undeniably fell down on their semi-final performance.
