I am playing with LEDs nowadays. I got them from nehru place. It was hard finding the place, only after asking about 15 people. So I am putting it here so that it goes online :). There is a building called vishal bhawan and in its basement there are lots of such shops. You can get resistors, capacitors, microchips, etc.
update: Also found Janak electronics in Hauz rani. Slightly more expensive than the vishal bhavan one, but it’s not that crowded.