Taxation on dollar income from canada

Hello Friends

I live in India and work for a couple of websites in Canada and US....I am a 3d Artist and get paid through Paypal ... The payment is converted into INR and credited to my ICICI bank a/c ....as (Royalty Payments).....

Am i eligible to pay taxes here in India, for last two years i have not filed any ITR..... My main source of income is from a website in Canada ... the good news is Since the company is in Canada .... they don't cut any taxes like in US....

But the websites from US i have to submit W8BEN form and some tax exemptions are given by them....,

But my main concern is how much tax i have to pay here since all my income is from abroad staying here in India....

Pls guide ....

Thanks