Flipkart's Big Billion Days, Amazon's annual festive sale to kick off from September 27

Flipkart's flagship sale, The Big Billion Days, is an important event for the company, and brings in a substantial portion of the its annual sales, much like it does for its competitors and other businesses in general. This year, quick commerce platforms like Zepto-owned Blinkit, Instamart and Mumbai-based Zepto are also preparing for an action-packed Diwali.