School/pre-school/daycare (New Delhi)

We are a couple with a 3 year son newly arrived in Delhi. We live in Gulmohar Park. We are trying to understand how the pre-school/schooling system works for our son and what our options near we live would be. I've visited a couple of pre-schools/day care centres (kidsnwhy & magic tree) and both say that most of their kids are under 3 because the when a child is 3 at the beginning of April they are eligible for school. However from what I have read school starts at 6. We want to send our son to some kind of pre/play-school (in the loose sense of the words) but are confused about what to look for.