4G emerged as the key driver of mobile data consumption in 2017 and 82 per cent of the mobile data traffic came from 4G in India, Nokia's annual "Mobile Broadband Index" study said on Thursday. The traffic grew 135 per cent year-on-year (YoY) with the rapid deployment of 4G networks and affordable devices in the country. 3G grew data grew 286 per cent in 2017, driven by an increased appetite for data consumption and better coverage.