Indian politicians spar over dodgy economic data as election nears

India may be the world's sixth largest, but most other things about economy are up for debate.

The Bharatiya Janata Party (BJP) is under fire for the release of new historical GDP figures that significantly downgraded growth during the years the opposition Congress party was in power, replacing old government estimates and those prepared by an independent committee.

The figures, released by the government's Central Statistics Office (CSO), showed growth in the 10 years of Congress rule to 2014 averaged 6.7 percent, below an average of 7.4% under the current government. A previous government estimate had growth under Congress at 7.8%.

P. Chidambaram, a former Congress finance minister, called the release "a joke". In response India's current finance minister, the BJP's Arun Jaitley, said the CSO was a credible organisation.

The fallout comes at a critical time for Prime Minister Narendra Modi.

India's economy grew a weaker-than-expected 7.1 percent in the July-September quarter, from a more than two-year high of 8.2 percent in the previous quarter, government data showed on Friday.

Modi faces a general election next year, when the performance of the economy under his pro-business administration compared with the Congress era is likely to dominate campaigning.

The spat has also alarmed India's top statisticians, who have long faced the difficult task of estimating growth and unemployment in an economy with hundreds of millions of informal workers, and dominated its financial press and political cartoons in recent days.

"The entire episode threatens to bring disrepute to India's statistical services," said an editorial in Mint, one of the country's leading business newspapers, on Friday.

A joke widely circulated on WhatsApp said the government would soon be reinterpreting the last cricket World Cup, in which India crashed out in the semi-finals, to say the country won based on a new methodology.