Reliance Jio clocked the highest 4G data download speed for six consecutive months during the first half of the current fiscal with an average throughput of almost 20 Mbps. This was against rivals, Bharti Airtel, Vodafone India and Idea Cellular, whose average mobile data speed could not even cross the 10 Mbps mark during the same period. As per latest numbers by the Telecom Regulatory Authority of India (Trai), Jio clocked 4G data speed of 14.7 Mbps, 19 Mbps, 22.3 Mbps, 19.9 Mbps, 22.3 Mbps and 20.6 Mbps during April, May, June, July, August and September, respectively. Its average 4G mobile data speed for the April-September period of FY19 stood at 19.8 Mbps, against Bharti\u2019s 9.6 Mbps, Vodafone (6.7 Mbps) and Idea (6.5 Mbps). A quick analysis shows that the three incumbents could not even breach the 10 Mbps mark during these six months, barring Bharti which managed a speed of 10 Mbps in August. During the 2017 calendar year (CY) as well, Jio ruled Trai\u2019s 4G mobile data speed charts for 12 consecutive months in a row. Mobile data speed has been a contentious issue with Bharti and Jio locking horns over which operator provides the fastest mobile data speed. Last year, Jio had moved the Advertising Standards Council of India (ASCI) against Bharti\u2019s TV commercial claiming itself as \u201cofficially\u201d the fastest network. The advertising watchdog asked Bharti to remove the ad, which the operator did. Jio has been continuously at the top on data released by Trai, which bases it on average of data speed samples collected from subscribers through crowd sourcing during speed test initiated by it and background tests initiated by its MySpeed app, while independent speed tests by noted mobile coverage mapping company, Open Signal, has put Bharti at the top. In April, Open Signal in its State of Mobile Networks in India report pegged Bharti's average 4G download speed at 9.31 Mbps, followed by Idea (7.27 Mbps), Vodafone (6.98 Mbps) and Jio at the bottom of the ladder with a speed of 5.13 Mbps. The coverage period was December 2017 to February 2018. To put an end to this controversy, Trai has initiated the process of reviewing mobile data speed methodology and came out with a white paper in February 2018, on the methodology, approach and evaluation criteria for its MySpeed app, which measures mobile data speeds of operators. The white paper, which analysed test set up and methodologies behind working of the app, concluded that collecting more data to validate test results like radio access technology (RAT), distance of user from the base transreceiver station (BTS), etc, can help in providing more insights on data speeds.