Vihaan :
I heard that in passive cooling overheating is major problem. Also I read the reviews of asus en210, people says overheating is major problem
It's only a 31W card. How can it overheat? Yes, if you don't have good case airflow, then maybe, but by itself, the card has no overheating issues.
Also, if you're going to go with the 210, you could go with the 610 as well. It's slightly faster than the 210, but is mostly sold with 2GB of VRAM. Get the 1GB variant, the 610 is not nearly fast enough to utilize 2GB of RAM
Of course, this is all assuming you have no use for a faster card. If you game at all, better spend a little more and go for a GTX750Ti or better.