Sales across the group fell 3.3% to 11.47 billion euros (£10.2 billion) in the quarter to June 30, with revenue in India plummeting 13.9% amid “continued price competition”.
Earlier this year, Vodafone booked a 3.7 billion euro (£3.2 billion) writedown on its Indian unit after striking a deal to merge the operation with Idea Cellular to help tackle a price war in the country.
In the UK, revenue fell 4.5% to 1.75 billion euros (£1.5 billion) as it was hit by falling sales and the impact of the pound’s plunge since the Brexit vote.
The deconsolidation of Vodafone Netherlands and foreign exchange movements also dented the firm’s performance in the period.
Better figures were seen in Spain and Italy, where the firm reported robust growth, along with Africa, the Middle East and Asia, with sales rising 1.2%, driven by a strong performance in Turkey.
Vodafone’s preferred measure of sales showed group service revenue up 2.2% at 10.28 billion euros (£9.23 billion).
Chief executive Vittorio Colao said: “We have made a good start to the year in Europe, where our commercial momentum remains robust, and growth accelerated across Africa, the Middle East and Asia Pacific.
“Although competition in India remains intense, service revenues stabilised compared with the prior quarter.
“We are gaining profitable market share in broadband, and a growing proportion of our customers now take our fully converged offers.
“Overall, this performance gives us confidence in reiterating our outlook for the year.”