Amazon India on Wednesday said that its main product categories saw strong sales growth during the Prime Day event, while it added more new members to its subscription programme than in any other week.

Prime is Amazon’s subscription programme, which offers subscribers fast product deliveries, additional discounts, video content and music streaming, among other services. It’s a key differentiator for Amazon in its battle with arch-rival Flipkart. To push its subscription programme in all its markets, Amazon announced a heavily-advertised Prime Day sale on 16 July that was extended by 12 hours.

At Amazon India, smartphone sales increased five times compared with the sales on a typical day, while that of large appliances jumped nine times and fashion products rose two times, the company said in a statement. Smartphones, large appliances and fashion are the three largest e-commerce product categories.

Amazon also said that 35% of new Prime members it added on Prime Day came from tier 2-3 towns. “Extending Prime Day to 36 hours this year allowed us to further reward members with unbeatable deals, access to exclusive new products and unforgettable experiences that highlight the many benefits of a Prime membership," Amazon India head Amit Agarwal said in a statement.

As with all sale events in India, there was a competing sale to Prime Day. After Amazon announced the event, Flipkart responded with its Big Shopping Days sale from 16-19 July. Such events are big drivers of e-commerce in India that is still largely dependent on discounts.