MUMBAI: Online fashion retailer Myntra will shut its website from May 1, in what is a definitive step towards becoming only a mobile app-based retailer , sources close to the development told TOI. This will be the first such instance of an e-commerce player transforming into a mobile-only entity as internet usage over smartphones surges in India.TOI first reported in its February 7 edition that Myntra may look to phase out its web presence sometime during this year. However, the decision to shutter the site has been advanced, said sources, who did not want to be named. Flipkart, which acquired Myntra a year ago, may also follow suit if the experiment goes down well with the fashion e-tailer Both Flipkart and Myntra have already closed down their mobile websites directing visitors to their respective apps. Mukesh Bansal, Myntra co-founder and head of com merce at Flipkart, did not respond to TOI's query on the closure of the e-tailer's site There is a 360-degree advertising and marketing campaign being planned by Myntra to announce its app-only presence which will be unveiled in the coming weeks, sources said.Currently , Myntra draws as much as 80% of its traffic and 70% of sales from its mobile app. Flipkart, too, registers more than 60% of sales through its app.Bansal had in the February 7 report said “we are (Myntra) 100% focused on mobile and making all our investments on the platform going forward“. In a recent interaction with TOI, Sachin Bansal, co-founder of Flipkart, had said that desktops weren't giving the same return on investments anymore compared to a few years ago. Bansal said Flipkart would keep an eye out for more acquisitions in the mobile space.Online shopper penetration (as a percentage of internet users) in India is expected to increase from 9% in 2013 to 36% in 2020, primarily led by mobile users, a recent Morgan Stanley report said. With mobile usage increasing, advertisement costs (primarily search engine optimization) are declining as traffic is increasing either directly to the website or through a mobile app. This is also increasing customer stickiness as once an app has been downloaded, customers generally visit that website before visiting any other site, the report said.Seeing the trend, over the past year or so younger startups have begun operation as mobile-only platforms, a shift from the concept of mobile-first adopted by the first wave on tech companies. The Internet & Mobile Association of India estimates that total internet users amounted to over 300 million in December 2014, with close to 60% via a mobile connection.Both Flipkart and Myntra, as well as some of the other e-commerce majors, have been pushing offers exclusively on their apps with the aim of getting consumers on to the platform. Most leading Indian e-commerce players have seen mobile contribute to greater than 50-60% of transactions today from under 5% a year ago as smartphone penetration has risen exponentially.