A report by OpenSignal on overall mobile data download speeds in India, from May 2017 to February 2018 found that Jio saw a drop in speeds - which had peaked in August last year - but stagnating from December to February.

Other leading operators - Airtel, Vodafone, and Idea - saw a reverse trend with improving mobile data speeds from September last year till February.

However, one must keep in mind that Jio is a 4G-only operator, while the rest also offer 3G and 2G networks.

OpenSignal's Kevin Fitchard pointed out that the reason behind faster download speeds for Airtel, Idea, and Vodafone wasn't because of an increase in actual speeds, but due to better 4G LTE availability. "The first thing we notice is that through the summer of 2017 overall speeds for Airtel, Idea and Vodafone were all relatively steady, but in September something happened that starts sending their overall download averages upwards. What we're seeing isn't an increase in LTE speeds or even 3G speeds - both metrics stayed relatively static over the last year. Instead, the three operators began expanding the reach of their LTE networks. Our 4G availability scores for all three operators increased significantly for all three operators in those 10 months. As more customers had access to faster LTE connections more often, overall speeds for Airtel, Idea, and Vodafone increased accordingly," Fitchard wrote in the report.

"It will be fascinating to see how this race in overall speed between Jio and Airtel plays out in the coming year. If Jio can pull another 4G network upgrade out of its hat, it could once again boost its overall speeds beyond Airtel's. But Airtel isn't sitting still. As it improves its network reach, bringing LTE connections to customers more often, its overall speed will likely continue to climb. In short: Jio's growth in overall speed will almost certainly come in big spurts, while Airtel's growth will probably be much more steady. And let's not discount Vodafone and Idea. Any improvement in 4G speed or 4G availability for either operator will help them close the overall speed gap created by the two leaders," Fitchard added.