The schema which I followed on Google developers site, does not help me trigger a Google now card, I am passing JSON inside the HTML tag and sending an Event-Registration email but nothing happens. Please provide help.
If you just copy and paste the JSON example that's on the documentation, you'll see that the startDate is in 2017:
"startDate": "2017-03-06T19:30:00-08:00"
Try inputting an earlier startDate, like today for example:
"startDate": "2015-06-04T10:30:00-08:00"
Otherwise, you won't see your card until March 6th 2017. If this is not the case, could you post your markup.