India will auction three slots each of third-generation wireless spectrum in most of its telecoms zones, including in the lucrative Delhi and Mumbai regions, from April 9, the telecoms ministry said on Thursday.

The government had earlier planned to auction four slots in Mumbai and two in Delhi. It did not give a reason for the change. The oft-delayed auction is expected to bring in $7.6 billion to federal coffers and help reduce the country's bloated fiscal deficit that is currently at a 16-year high. Analysts say incumbent GSM telecoms firms like Bharti Airtel and Vodafone Essar Ltd need the efficient 3G spectrum to meet cut-throat competition unleashed by new entrants like Telenor without straining their networks. Of the 22 telecoms zones, 17 will see auctions for three slots each, while four slots each would be up for bids in the rest, the telecoms ministry said.