"With this additional investment of USD 2 billion, our team can continue to think big, innovate, and raise the bar for customers in India," he said.

At current scale and growth rates, India is on track to be Amazon's fastest country ever to a billion dollars in gross sales, he said.

"We have never seen anything like this," Bezos said. In India, Amazon sells over 17 million products across categories like books, apparel and electronics from a growing base of thousands of small and medium-sized businesses.

Apart from smaller e-commerce portals, Amazon competes head on with Flipkart and Snapdeal. In the past few months it has raised the bar with introducing same-day delivery and ramping-up its logistics among others.

Earlier this week, Amazon said it will open 5 new centres across India in addition to its two fulfilment centres (FCs) in Mumbai and Bangalore. The FCs will be set up in Delhi, Chennai, Jaipur, Ahmedabad and Tauru (outskirts of Gurgaon).

This, it said, would help in faster delivery of products. With the addition of the five centres, Amazon's total storage capacity will almost double to over half a million sq feet.

READ MORE: Andhra Pradesh To Replicate Kochi-Model Startup Village