I'm not sure what promotion you are referring to.
A number of credit cards have promotions where you get extra miles on ticket purchases. Most airlines, if you have their branded credit card, will give you 2x miles on purchases on that airline - for example, if you have a Delta Skymiles card and buy a $2,000 ticket, you will get 4,000 points, not 2,000. Some non-branded cards give extra miles - Chase Sapphire Preferred gives 2x on travel, Amex Preferred Rewards Gold gives 3x on airfare.
Note that these are points for purchases, not miles flown. If you buy a $2,000 ticket to fly 10,000 miles, you will get bonuses based on 2000, not 10000.
These are nice incentives, but they won't make a huge huge dent in your ticket cost. Then again, since a paid business class ticket from India to the USA (is that where you live) could be quite pricey, getting the extra miles might be a nice bonus. However, you should at least consider trying to use miles to pay for the trip. Under many conditions, using miles for international business and first-class travel is the most efficient use of miles/points.