NEW DELHI: Reliance Jio continued to top the average 4G download speed chart, beating its nearest rival Airtel with almost double data speed, according to a report by the Telecom Regulatory Authority of India (Trai) for January.Jio's 4G network registered an average download speed of 18.8 megabits per second (Mbps), while Airtel network clocked a speed of 9.5 Mbps.Airtel, Vodafone and Idea have a mix of 2G, 3G and 4G networks, but Jio provides only 4G services According to the Trai report, Vodafone registered an average speed of 6.7 Mbps, while Idea had average speed of 5.5 Mbps on 4G network.Though Vodafone and Idea have merged their mobile businesses, Trai measured their performance separately as the integration of networks of both the companies is currently on.Reliance Jio was the fastest 4G operator in 2018 with the highest average download speed for the last 13 months.Idea, however, continued to top the chart in terms of average 4G upload speed. After a continuous decline in upload speed between October and December, upload speed on Idea and Vodafone network picked up in January.In January, Idea 4G network registered an average upload speed of 5.8 Mbps, followed by Vodafone with upload speed of 5.4 Mbps.Jio followed Vodafone with an upload speed of 4.4 Mbps and Airtel with 3.8 Mbps.The average speed is computed by Trai based on the data it collects across India with the help of its MySpeed application on a real-time basis.