What is your current salary? Office Life 1

We work for some companies in life where hiring people is also our JD as a team leads. During my experience, I hire nearly 50+ peoples for my different jobs and teams.

2nd, I never go for an interview in my whole career (A bit strange) but in the last few days, I talk with 2 HR managers about a job. They ask me a strange question, “What is your current salary?”

I cant understand why they asking me about my current salary. Are they going to decide my salary according to my previous salary? If a person joins a job with low skill sets and improves himself a lot during a previous job, then how HR going to evaluate the improvement of our skills?

Okay, HR guys, in case I am doing a job just because of some personal reason and getting a low salary. If my personal reason is now finished, are you going to evaluate my current salary demand with previous?