Tata had 3300GB and Airtel had 3333GB cap in their ‘unlimited’ plans before Jio came up with unlimited. Jio copied it. I also asked the same thing on 31 august itself, is this number random or has a story?
These calculations are based on average speed which a user can expect over a duration of one month. Because usage varies, has its peaks and troughs, so an assumed average speed of a month is used for calculating data usage.
They have taken a baseline of 10mbps or 1.25 (10/8) MBps constant and stable speed for a duration of one month.
10mbps x 60s x 60m x 24h x 31d=2,67,84,000mbit