thank you for detailed reply, actually I just Googled it and it told me required an ETA, so that I applied for an E-VISA here and uploaded all documents on their portal, and paid 200 Rs [ 35 dollars] they approved the visa and got by email in 3 days, so I was just confused wheatear to apply or not..
Well, I have applied for an ETA, and they granted me a 3 month visa... it took 3 days to get it.. if you have enough time, you could use it by the ETA portal.