India retains slot of world's fastest economy
Gross domestic product expanded 7.1 percent year-on-year in the three months from April-June, down from the stellar growth of 7.9 percent in the preceding quarter, according to the statistics ministry.
The numbers also fell short of economists' expectations, with most predicting a slight slowdown in GDP growth to around 7.6 percent for the quarter.
However, India retained its place as the world's fastest-growing major economy, with growth having outpaced Asian rival China for more than a year.
India's rosy GDP figures have drawn questions since the government in January 2015 revised its base year to 2011-12 and introduced new ways of calculating growth which it said were closer to international standards.
The disappointing data came as US Secretary of State John Kerry said India's economy would only be able to maintain its impressive growth if its bureaucracy ceased to be "an expert in setting up roadblocks".
Speaking on a visit to New Delhi, Kerry said red tape and a lack of transparency continued to deter entrepreneurs and foreign investors.
Prime Minister Narendra Modi has made kickstarting growth a priority since taking power in 2014. Investors have praised recent reforms including a bankruptcy code and a new Goods and Services Tax that will create a single market across India.
However, many investors have been frustrated with the pace of reforms in the world's second-most populous nation.