score:2
I am not sure about the link you have posted, but this is the official website for the Indian eVisa https://indianvisaonline.gov.in/evisa/tvoa.html
The official website will ask you about the date of arrival, the port of entry and duration of stay. However, you can arrive on a different date as long as it falls within the duration/validity they have granted you.
Also, you don't have to book your ticket before applying to the eVisa.
The aforementioned is based on my experience.
Upvote:1
In 2017, I traveled to India on an eVisa, and did not have my ticket booked before my application.
You can also see the sample form here, and it's not required.