Shares in Idea Cellular fell 1.8 per cent today. This follows the company's spectrum renewal costs escalating to Rs 21,880 crore ($3.49 billion), up 73.8 per cent, according to Edelweiss Securities.

"Gujarat and UP (West), must-win circles for Idea, clocked price escalation of 58.7 per cent and 224.3 per cent over reserve prices, respectively," Edelweiss said.

"The ratio of debt to EBITDA of Idea, which has the highest spectrum renewal risk, will rise to 3x because of spectrum-related costs, from about 1.1x now," S&P says.

The formal bidding process to auction airwaves, which began last week, could take days or even weeks to conclude, depending on bidding intensity. ($1 = 62.7675 Indian rupees)

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