Reliance Jio is touted to be the fastest growing telecom operator in the world, and credit for that expansion will arguably go to its introductory free offer. Now, a new report from Credit Suisse claims that while Reliance Jio enjoys the most amount of network coverage, its 4G speed trails behind its competitor Airtel.

According to a report released by financial services company Credit Suisse, Airtel 4G offers the best 4G speeds among the other competitors in India. The download speed of Airtel is at 12Mbps; while Reliance Jio, Vodafone, and Idea all come a close second with 7-8Mbps download speeds.

"Our conclusion is that Reliance Jio's network coverage is significantly ahead of the other operators. Reliance Jio has good coverage in 80 percent plus of cities surveyed, compared to less than 30 percent for the others. The difference is even more stark when compared only with 4G networks of incumbents (sub-15 percent of cities)," the report said.

The report claimed that the slow speeds on Reliance Jio was probably due to the load on its servers. Reliance Jio reportedly carries 90 percent plus of all data traffic in the country currently while its network capacity share is closer to 35 percent only.

"We have already started seeing the impact of Jio on the incumbents' numbers (Bharti 3Q). Our study here shows Jio has built a significant lead in terms of network coverage, and the incumbents have a fair amount of catch up to do (especially on 4G). Importantly, going by recently announced enhanced capex plans, the company continues to invest. Overall, we continue to see significant pressure on fundamentals in coming quarters from Jio," it said.

The report is based on the study of over 30 Indian cities that represent a "significant chunk of current data demand and revenues." Reliance Jio's free introductory offer was extended till March 31, and even after the offer ends, the plan prices are much lesser than its competition. Companies like Airtel, Vodafone, and Idea have been hit hard by Reliance Jio's entry, and Airtel even recorded its lowest profits in four years. Telecom operators have been launching lucrative offers to combat the Reliance Jio effect as well, case in point being Vodafone which recently launched its Vodafone RED plans with unlimited calling.