Competition is fierce and spectrum is short, Reliance Jio spent $20B, built one of the best networks in the world, and gained 100M customers in the first year. Mukesh Ambani's aggressive plans for the 4G $20 (refundable) feature phone will probably add 100M more in the next year or so. Hundreds of millions of Indians are still on 2G. Ambani is ready to spend $B+ in subsidies to bring them to Jio 4G.
Giant Tata is closing their #4 mobile network, putting 10,000 out of work, writing off billions, and selling off cheaply to Bharti.. #5 Reliance Communications, Ambani's brother's company, is likely to follow. They couldn't compete in the price war. Vodafone and Idea, #2 & #3, are merging to stay alive
#1 Bharti's strategy in response includes a huge build of Massive MIMO, just announced. Danish Khan now reports the other two likely survivors, Jio and Vodafone/Idea, will also do Massive.