Is yellow (concentrated)urine dangerous? anything to be worried? any possible health issues?

Depends: Urine is usually yellow of different concentration. Depends if its cloudy or clear , foul smelling or normal urine smell. Intensity of color is a matter of concentration. Drink more water and if color gets lighter probably you are ok. It's worth to have your urine checked , also your kidney functions. Sometimes certain foods can change color and smell of your urine