May I use my former-yet-active email address of an institute as a contact channel in my current CV? Since I was a master student in (the North American) X university, my email roboticist@x.edu has been still active, even though it is a couple of years that I have left that university. Now, I'm about to finish my Ph.D. in (the European) Y university, and Y will be immediately closing my current roboticist@y.edu upon my graduation. I have heard that writing an unprofessional email address, e.g., roboticist@gmail.com, in the contact information section of an academic CV does not make a good impression on readers. So, I am wondering whether I may use the still-active email of mine corresponding to X in my CV for that purpose. My main concern is two fold: whether or not I am allowed to do that in view of X, and whether or not it is ethically a sound decision because it can mislead readers thinking that I am currently affiliated with X.
PS. My question relatively resembles what are discussed here and here, but the difference is that those questions' contexts are paper affiliation and contacting professors, respectively. However, mine is about the contact information section of a CV.
I can see no legal or ethical problem with using an email address from a former institution, as long as you are clear about your current affiliations in your communications.
That said, there may be better options:

Professional societies often offer an option of an email address. As a roboticist, for example, you can almost certainly affiliate with the IEEE, whose excellent email service I use myself.
One of your former institutions may offer an alumni email address (or at least forwarding service). I believe this is more common in the US than Europe, but it's fairly arbitrary which institutions do and do not offer this.

Both of these can typically be set up very quickly and also have the advantage of being permanent, even when you change institutions.